Abstract
The present invention provides compositions and methods for detecting
the presence of the corn event MON863 DNA inserted into the corn genome
from the transformation of the recombinant construct containing a
Cry3Bb gene and of genomic sequences flanking the insertion site.
The present invention also provides the corn event MON863 plants,
progeny and seeds thereof that contain the corn event MON863 DNA.
Claims
21. A biological sample derived from a corn event MON863 plant, tissue,
or seed, wherein said sample comprises a nucleotide sequence which
is or is complementary to a sequence selected from the group consisting
of SEQ ID NO:1, and SEQ ID NO:2, and wherein said sequence is detectable
in said sample using a nucleic acid amplification or nucleic acid
hybridization method.
22. The biological sample of claim 21 comprising plant, tissue,
or seed of transgenic corn event MON863 having seed deposited with
American Type Culture Collection (ATCC) with Accession No. PTO-2506.
23. The biological sample of claim 22 wherein said sample is selected
from the group consisting of an extract obtainable from the transgenic
corn plant event MON863, and wherein said extract comprises one
or more of the nucleotide sequences selected from the group consisting
of SEQ ID NO:1, SEQ ID NO:2, and the complement thereof.
24. The biological sample of claim 23 wherein said sample is selected
from the group consisting of corn flour, corn meal, corn syrup,
corn oil, corn starch, and cereals manufactured in whole or in part
to contain corn by-products.
25. An extract derived from a corn even MON863 plant, tissue, or
seed comprising a nucleotide sequence which is or is complementary
to a nucleotide sequence selected from the group consisting of SEQ
ID NO:1, and SEQ ID NO:2.
26. The extract of claim 25 wherein said sequence is detectable
in said extract using a nucleic acid amplification or nucleic acid
hybridization method.
27. The extract of claim 26 comprising plant, tissue, or seed of
transgenic corn plant event MON863.
28. The extract of claim 27 wherein said sample is selected from
the group consisting of corn flour, corn meal, corn syrup, corn
oil, corn starch, and cereals manufactured in whole or in part to
contain corn by-products.
29. A corn event MON 863 having seed deposited with American Type
Culture Collection (ATCC) with Accession No. PTA-2506.
30. The corn event of claim 29, wherein the genome of said event
or progeny thereof comprises a DNA molecule selected from the group
consisting of SEQ ID NO:1 and SEQ ID NO:2.
31. Plant parts of the corn event of claim 30.
Description
[0001] This application is a 35USC.sctn.371 application of PCT/US03/22860,
filed Jul. 23, 2003, which claims the benefit of priority to U.S.
Provisional Application 60/399,279, filed Jul. 29, 2002.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of plant molecular
biology. The invention more specifically relates to a coleopteran
resistant corn plant (Zea mays) PV-ZMIR13, designated MON863, and
to seeds and progeny of the corn plant MON863. The corn plant MON863
and its progeny are particularly resistant to Diabrotica vergifera,
Diabrotica undecimpunctata, and Leptinotarsa decemlineata.
[0003] The present invention more specifically also relates to
a DNA construct inserted into the corn plant genome in event MON863
for conferring resistance to insect infestation by a coleopteran
species. The present invention also relates to assays for detecting
the presence of a corn plant MON863 DNA in a sample and compositions
thereof.
BACKGROUND OF THE INVENTION
[0004] Corn is an important crop and is a primary food source in
many areas of the world. The methods of biotechnology have been
applied to corn plants for improvement of the agronomic traits and
the quality of the product. Expression of foreign genes in plants
is known to be influenced by their chromosomal position, perhaps
due to chromatin structures (e.g., heterochromatin) or the proximity
of transcriptional regulation elements (e.g., enhancers) close to
the integration site (Weising et al., Ann. Rev. Genet 22:421-477,
1988). For this reason, it is often necessary to screen a large
number of events in order to identify an event characterized by
optimal expression of an introduced gene of interest. For example,
it has been observed in plants and in other organisms that there
may be a wide variation in levels of expression of an introduced
gene among events. There may also be differences in spatial or temporal
patterns of expression, for example, differences in the relative
expression of a transgene in various plant tissues, that may not
correspond to the patterns expected from transcriptional regulatory
elements present in the introduced gene construct. For this reason,
it is common to produce hundreds to thousands of different events
and screen those events for a single event that has desired transgene
expression levels and patterns for commercial purposes. An event
that has desired levels or patterns of transgene expression is useful
for introgressing the transgene into other genetic backgrounds by
sexual outcrossing using conventional breeding methods. Progeny
of such crosses maintain the transgene expression characteristics
of the original transformant. This strategy is used to ensure reliable
gene expression in a number of varieties that are well adapted to
local growing conditions.
[0005] It would be advantageous to be able to detect the presence
of a particular event in order to determine whether progeny of a
sexual cross contain a transgene of interest. In addition, a method
for detecting a particular event would be helpful for complying
with regulations requiring the premarket approval and labeling of
food derived from recombinant crop plants, for example. It is possible
to detect the presence of a transgene by any well-known nucleic
acid detection method such as the polymerase chain reaction (PCR)
or DNA hybridization using nucleic acid probes. These detection
methods generally focus on frequently used genetic elements, such
as promoters, terminators, marker genes, etc. As a result, such
methods may not be useful for discriminating between different events,
particularly those produced using the same DNA construct unless
the sequence of chromosomal DNA adjacent to the inserted DNA ("flanking
DNA") is known. An event-specific PCR assay is discussed, for
example, by Windels et al. (Med. Fac. Landbouww, Univ. Gent 64/5b:
459-462, 1999), who identified glyphosate tolerant soybean event
40-3-2 by PCR using a primer set spanning the junction between the
insert and flanking DNA, specifically one primer that included sequence
from the insert and a second primer that included sequence from
flanking DNA.
SUMMARY OF THE INVENTION
[0006] According to one preferred embodiment of the present invention,
compositions and methods are provided for detecting the presence
of the transgene/genomic insertion region from a novel corn plant
PV-ZMIR13, designated MON863. DNA sequences are provided that comprise
at least one junction sequence of MON863 selected from the group
consisting of SEQ ID NO:1 (arbitrarily assigned 5' end insert-to-genome
junction) and SEQ ID NO:2 (arbitrarily assigned 3' end insert-to-genome
junction) and complements thereof, wherein the junction sequence
spans the junction between a heterologous DNA inserted into the
corn genome and the DNA from the corn cell flanking the insertion
site and is diagnostic for the event.
[0007] According to another preferred embodiment of the present
invention, DNA sequences that comprise the novel transgene/genomic
insertion region, SEQ ID NO:3 (sequence containing the arbitrarily
assigned 5'end of the inserted DNA) and SEQ ID NO:4 (sequence containing
the arbitrarily assigned 3'end of the inserted DNA) for example,
are disclosed.
[0008] According to still another preferred embodiment of the present
invention, the DNA sequences that comprise at least from about 11
to about 50 or more nucleotides of the 5' transgene portion of the
DNA sequence of SEQ ID NO:7 and a similar length of 5' flanking
corn DNA sequence of SEQ ID NO:5, or a similar length of 3' transgene
portion of the DNA sequence of SEQ ID NO:8 and a similar length
of 3'flanking corn DNA of SEQ ID NO:6, for use as DNA primers in
DNA amplification methods are also disclosed in the present invention.
Amplicons produced using these primers are diagnostic for corn event
MON863. An amplicon produced by a first DNA primer homologous or
complementary to SEQ ID NO:7 coupled with a second DNA primer homologous
or complementary to SEQ ID NO:5, when both are present together
in a reaction mixture with corn event MON863 DNA in a sample are
an aspect of the present invention. An amplicon produced by a third
DNA primer homologous or complementary to SEQ ID NO:8 coupled with
a fourth DNA primer homologous or complementary to SEQ ID NO:6,
when both are present together in a reaction mixture with corn event
MON863 DNA in a sample, are another aspect of the present invention.
The corn plant MON863 and progeny derived therefrom that contain
these DNA sequences used in a DNA amplification reaction to provide
one or more diagnostic amplicons are aspects of the invention.
[0009] According to yet another preferred embodiment of the present
invention, methods of detecting the presence of a DNA corresponding
to the corn event MON863 event in a sample are provided. Such methods
comprise the steps of: (a) contacting a biological sample suspected
of containing an event MON863 DNA with a primer pair that, when
used in a nucleic acid amplification reaction with said DNA, produces
an amplicon that is diagnostic for the corn event MON863; (b) performing
a nucleic acid amplification reaction, thereby producing the amplicon;
and (c) detecting the amplicon. The amplicons specifically exemplified
herein correspond to a first amplicon of about 508 base pairs as
set forth in SEQ ID NO:3 and a second amplicon of about 584 base
pairs as set forth in SEQ ID NO:4, or longer or shorter amplicons,
wherein said first amplicon contains as least a nucleotide sequence
corresponding to SEQ ID NO:1 from about nucleotide 1 through about
nucleotide 11 or from about nucleotide 10 through about nucleotide
20 and said second amplicon contains at least a nucleotide sequence
corresponding to SEQ ID NO:2 from about nucleotide 1 through about
nucleotide 11 or from about nucleotide 10 through about nucleotide
20.
[0010] According to yet another preferred embodiment of the present
invention, methods of detecting the presence of a DNA corresponding
to the MON863 event in a sample are provided. Such methods comprise
the steps of: (a) contacting a biological sample suspected of containing
an event MON863 DNA with a probe that hybridizes under stringent
hybridization conditions with said DNA and that does not hybridize
under stringent hybridization conditions with DNA from a control
corn plant that does not contain an inserted DNA derived from pMON25097;
(b) subjecting the sample and the probe to stringent hybridization
conditions; and (c) detecting hybridization of the probe to the
genomic DNA, wherein detection of probe binding to said DNA is diagnostic
for the presence of event MON863 DNA in said sample.
[0011] According to a further preferred embodiment of the present
invention, there is provided a novel corn plant MON863, that comprises
DNA sequences comprising the novel transgene/genomic insertion regions
as set forth in SEQ ID NO:3 and SEQ ID NO:4. The seeds of the plants
of MON863, the progeny of the plants of MON863 and the methods for
producing a corn plant by crossing the corn plant MON863 with itself
or with another corn plant are further embodiments of the present
invention.
[0012] The foregoing and other preferred embodiments of the present
invention will become more apparent from the following detailed
descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS AND SEQUENCES
DESCRIPTION OF DRAWINGS
[0013] FIG. 1 illustrates a plant expression vector PV-ZMIR13,
also designated herein as pMON25097, from which the corn rootworm
event MON863 is generated through particle acceleration technology
using a Mlu I restriction fragment from about nucleotide position
149 through about nucleotide position 4840.
[0014] FIG. 2 is a graphical map illustrating the general organization
of the elements comprising the heterologous nucleic acid sequences
inserted into the corn event MON863 genome and essentially sets
forth the positions at which the inserted nucleic acid sequences
are linked to corn genomic DNA sequences designated herein as corn
genomic nucleic acid sequences which flank the ends of the inserted
heterologous DNA sequences; the corn event MON863 being characterized
as follows: corn genomic DNA [1] flanking the arbitrarily assigned
5' end of the full length primary functional inserted DNA sequence
is adjacent to a non-naturally occurring CaMV35S AS4 promoter sequence
[2] (P-CaMV.AS4, SEQ ID NO:17) operably connected to a wheat chlorophyll
A/B binding protein untranslated leader sequence [3] (L-Ta.hcb1,
SEQ ID NO:18) operably connected to a rice actin intron sequence
[4] (I-Os.Act1, SEQ ID NO:19) operably connected to a non-naturally
occurring sequence encoding Cry3Bb variant protein [5] (SEQ ID NO:20)
operably connected to a wheat heat shock Hsp17 transcription termination
and polyadenylation sequence [6](T-Ta.Hsp17, SEQ ID NO:21), and
the full-length primary functional inserted DNA sequence being flanked
by the corn genomic DNA at the arbitrarily assigned 3' end [7],
in which the junction between [1] and [2] ([8]) corresponds to SEQ
ID NO:1, and the junction between [6] and [7] ([9]) corresponds
to SEQ ID NO:2.
DESCRIPTION OF SEQUENCES
[0015] SEQ ID NO:1 corresponds to a junction sequence between corn
genome and inserted DNA that is diagnostic for the arbitrarily assigned
5' end of the full-length primary functional inserted DNA sequence
in the corn event MON863.
[0016] SEQ ID NO:2 corresponds to a junction sequence between corn
genome and inserted DNA that is diagnostic for the arbitrarily assigned
3' end of the full-length primary functional inserted DNA sequence
in the corn event MON863.
[0017] SEQ ID NO:3 corresponds to the sequences represented substantially
by [1] and [2] of FIG. 2.
[0018] SEQ ID NO:4 corresponds to the sequences represented substantially
by [6] and [7] of FIG. 2.
[0019] SEQ ID NO:5 corresponds to the partial corn genome DNA sequence
that is adjacent to and flanking the 5' end of the arbitrarily assigned
5' end of the partial Cry3Bb DNA coding sequence inserted in the
corn event MON863.
[0020] SEQ ID NO:6 corresponds to the partial corn genome DNA sequence
that is adjacent to and flanking the 3' end of the arbitrarily assigned
3' end of the partial Cry3Bb DNA coding sequence inserted in the
corn event MON863.
[0021] SEQ ID NO:7 corresponds to the sequence of the arbitrarily
assigned 5' end of the partial Cry3Bb DNA coding sequence inserted
in the corn event MON863.
[0022] SEQ ID NO:8 corresponds to the sequence of the arbitrarily
assigned 3' end of the partial Cry3Bb DNA coding sequence inserted
in the corn event MON863.
[0023] SEQ ID NO:9 corresponds to a 5' primer sequence (primer
A) complementary to a part of the corn genomic DNA sequence identified
as flanking the arbitrarily assigned 5' end of the full length primary
functional inserted DNA sequence in the corn event MON863, and when
paired with a primer corresponding to the reverse complement of
the sequence set forth in SEQ ID NO:10 and template DNA of the corn
event MON863, produces an amplicon comprising SEQ ID NO:3 that is
diagnostic for the corn event MON863 DNA in a sample.
[0024] SEQ ID NO:10 corresponds to the reverse complement of a
3' primer sequence (primer B) complementary to a part of the arbitrarily
assigned 5' end sequence of the full length primary functional DNA
inserted into the corn genome in the corn event MON863, and when
paired with a primer corresponding to the sequence set forth in
SEQ ID NO:9 and template DNA of the corn event MON863, produces
an amplicon comprising SEQ ID NO:3 that is diagnostic for the corn
event MON863 DNA in a sample.
[0025] SEQ ID NO:11 corresponds to a 5' primer sequence (primer
C) complementary to part of the arbitrarily assigned 3' end sequence
of the full length primary functional DNA inserted into the corn
genome in the corn event MON863, and when paired with a primer corresponding
to the reverse complement of the sequence set forth in SEQ ID NO:12
and template DNA of the corn event MON863, produces an amplicon
having SEQ ID NO:4 that is diagnostic for the corn event MON863
DNA in a sample.
[0026] SEQ ID NO:12 corresponds to the reverse complement of a
3' primer sequence (primer D) complementary to a part of the corn
genomic DNA sequence identified as flanking the arbitrarily assigned
3' end of the full length primary functional inserted DNA sequence
in corn event MON863, and when paired with a primer corresponding
to the sequence set forth in SEQ ID NO:11 and the template DNA of
the corn event MON863, produces an amplicon having SEQ ID NO:4 that
is diagnostic for corn event MON863 DNA in a sample.
[0027] SEQ ID NO:13 corresponds to a 5' genome walker primer 1.
[0028] SEQ ID NO:14 corresponds to a 5' genome walker primer 2.
[0029] SEQ ID NO:15 corresponds to a 3' genome walker primer 1.
[0030] SEQ ID NO:16 corresponds to a 3' genome walker primer 2.
[0031] SEQ ID NO:17 corresponds to CaMV35S AS4 promoter sequence.
[0032] SEQ ID NO:18 corresponds to a wheat chlorophyll A/B binding
protein untranslated leader sequence (L-Ta.hcb1).
[0033] SEQ ID NO:19 corresponds to a rice actin intron sequence
(I-Os.Act1).
[0034] SEQ ID NO:20 corresponds to a non-naturally occurring sequence
encoding a Cry3Bb variant protein.
[0035] SEQ ID NO:21 corresponds to wheat heat shock Hsp17 transcription
termination and polyadenylation sequence (T-Ta.Hsp17).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] The following definitions and methods are provided to better
define the present invention and to guide those of ordinary skill
in the art in the practice of the present invention. Unless otherwise
noted, terms are to be understood according to conventional usage
by those of ordinary skill in the relevant art. Definitions of common
terms in molecular biology may also be found in Rieger et al., Glossary
of Genetics: Classical and Molecular, 5th edition, Springer-Verlag:
New York, 1991; and Lewin, Genes V, Oxford University Press: New
York, 1994. The nomenclature for DNA bases as set forth at 37 CFR
.sctn. 1.822 is used.
[0037] As used herein, the term "biological sample",
or "sample", is intended to include nucleic acids, polynucleotides,
DNA, RNA, tRNA, cDNA, and the like in a composition or fixed to
a substrate which enables the sample to be subjected to molecular
probe analysis or thermal amplification using oligonucleotide probes
and/or primers.
[0038] As used herein, the term "corn" means Zea mays
or maize and includes all plant varieties that can be bred with
corn, including wild maize species.
[0039] As used herein, the term "comprising" means "including
but not limited to".
[0040] As used herein, the term "diagnostic" refers to
the fact that, for the purposes of identifying nucleic acid sequences
as those contained within or derived from the corn event MON863,
any one or more of the novel DNA sequences set forth herein comprise
the corn genome flanking sequences adjacent to and linked to the
arbitrarily assigned ends of the inserted heterologous DNA sequences
are necessary and sufficient as being descriptive as a distinguishing
characteristic of the corn event MON863 genome, so long as the sequence
comprises at least a part of one of the ends of the inserted heterologous
DNA sequence or the corn genome sequence flanking or adjacent to
one of these ends and includes at least the two nucleotides, the
di-nucleotide, comprising the point at which the corn genome sequence
and the inserted heterologous DNA sequence are linked together by
a phosphodiester bond. It is well known in the art that a sequence
which is diagnostic for a particular event, such as those disclosed
herein for the corn event MON863, which is not present in a particular
sample containing corn genome nucleic acids, is indicative that
the sample does not contain the diagnostic sequence and therefore
the nucleic acids in the sample are not or were not derived from
and have not been contained within the genome of the corn event
MON863. In addition, additional novel and diagnostic sequences are
present within the corn event MON863 DNA as exemplified herein selected
from the group consisting of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3,
and SEQ ID NO:4 and complements thereof.
[0041] A transgenic "event" is produced by transformation
of plant cells with a heterologous DNA, i.e., a nucleic acid construct
that includes a transgene of interest, regeneration of a population
of plants resulting from the insertion of the transgene into the
genome of the plant, and selection of a particular plant characterized
by insertion into a particular genome location. The term "event"
refers to the original transformant and progeny of the transformant
that include the heterologous DNA. The term "event" also
refers to progeny produced by a sexual outcross between the transformant
and another variety that include the heterologous DNA. Even after
repeated backcrossing to a recurrent parent, the inserted DNA and
flanking DNA from the transformed parent is present in the progeny
of the cross at the same chromosomal location. The term "event"
also refers to DNA from the original transformant comprising the
inserted DNA and flanking genomic sequence immediately adjacent
to the inserted DNA that would be expected to be transferred to
a progeny that receives inserted DNA including the transgene of
interest as the result of a sexual cross of one parental line that
includes the inserted DNA (e.g., the original transformant and progeny
resulting from selfing) and a parental line that does not contain
the inserted DNA.
[0042] It is also to be understood that two different transgenic
plants can also be mated to produce offspring that contain two or
more independently segregating exogenous genes (exogenous genes
referring nucleotide sequences that are not naturally occurring
in the plant genome, i.e., heterogeneous to the corn plant). Selfing
of appropriate progeny can produce plants that are homozygous for
any combination of the exogenous genes. Backcrossing to a parental
plant and out-crossing with a non-transgenic plant are also contemplated,
as is vegetative propagation. Descriptions of other breeding methods
that are commonly used for different traits and crops can be found
in one of several references, e.g., Fehr, in Breeding Methods for
Cultivar Development, Wilcox J. ed., American Society of Agronomy,
Madison Wis. (1987).
[0043] A "probe" is an isolated nucleic acid to which
a conventional detectable label or reporter molecule, e.g., a radioactive
isotope, ligand, chemiluminescent agent, or enzyme may be linked
or attached. Such a probe is complementary to a sequence within
a target nucleic acid, in the case of the present invention, to
a sequence of genomic DNA from the corn event MON863 whether from
a corn plant or from a sample that includes DNA from the event.
Probes according to the present invention include not only deoxyribonucleic
or ribonucleic acids but also polyamides and other probe materials
that bind specifically to a target DNA sequence and can be used
to detect the presence of that target DNA sequence.
[0044] "Primers" are isolated nucleic acid probes that
are annealed to, for any given single primer, a complementary target
DNA sequence by nucleic acid hybridization to form a hybrid between
the primer and the target DNA sequence, and then extended along
the target DNA strand by a polymerase, e.g., a DNA polymerase. Primer
pairs of the present invention refer to two or more different primer
sequences for is in amplification of a nucleic acid sequence that
is between and linked to the target sequences designated as the
reverse complement or substantially the reverse complement of the
primers, e.g., by the polymerase chain reaction (PCR) or other conventional
nucleic-acid amplification methods.
[0045] Probes and primers are generally from about 11 nucleotides
or more in length, preferably from about 18 nucleotides or more
in length, more preferably from about 24 nucleotides or more in
length, and most preferably from about 30 nucleotides or more in
length. Such probes and primers hybridize specifically to a target
sequence under high stringency hybridization conditions. Preferably,
probes and primers according to the present invention have complete
sequence similarity with the target sequence, although probes differing
from the target sequence and that retain the ability to hybridize
to target sequences may be designed by conventional methods.
[0046] Methods for preparing and using probes and primers are described,
for example, in Molecular Cloning: A Laboratory Manual, 2nd ed.,
vol. 1-3, ed. Sambrook et al., Cold Spring Harbor Laboratory Press,
Cold Spring Harbor, N.Y., 1989 (hereinafter, "Sambrook et al.,
1989"); Current Protocols in Molecular Biology, ed. Ausubel
et al., Greene Publishing and Wiley-Interscience, New York, 1992
(with periodic updates) (hereinafter, "Ausubel et al., 1992");
and Innis et al., PCR Protocols: A Guide to Methods and Applications,
Academic Press: San Diego, 1990. PCR-primer pairs can be derived
from a known sequence, for example, by using computer programs intended
for that purpose such as Primer (Version 0.5, .COPYRGT. 1991, Whitehead
Institute for Biomedical Research, Cambridge, Mass.).
[0047] Primers and probes constructed based on the flanking DNA,
insert sequences, and junction sequences disclosed herein can be
used to confirm the presence of the disclosed sequences in a sample
by conventional methods, e.g., by recloning and sequencing such
sequences.
[0048] Any single nucleic acid probe or primer of the present invention
hybridizes under stringent conditions to a specific target DNA sequence.
Any conventional nucleic acid hybridization or amplification method
can be used to identify the presence of DNA from a transgenic event
in a sample. Nucleic acid molecules or fragments thereof specifically
hybridize to other nucleic acid molecules under certain circumstances.
As used herein, two different nucleic acid molecules each comprising
different sequences, are said to specifically hybridize to one another
if the two molecules form an anti-parallel, double-stranded nucleic
acid structure. A nucleic acid molecule is said to be the "complement"
of another nucleic acid molecule if they exhibit complete complementarity.
As used herein, molecules are said to exhibit "complete complementarity"
when every nucleotide of one of the molecules is complementary to
a nucleotide of the other. Two molecules are said to be "minimally
complementary" if they can hybridize to one another with sufficient
stability to permit them to remain annealed to one another under
at least conventional "low-stringency" conditions. Similarly,
the molecules are said to be "complementary" if they hybridize
to one another with sufficient stability to permit them to remain
annealed to one another under conventional "high-stringency"
conditions. Conventional stringency conditions are described by
Sambrook et al., 1989, and by Haymes et al. (In: Nucleic Acid Hybridization,
A Practical Approach, IRL Press, Washington, D.C., 1985). Departures
from complete complementarity are therefore permissible, as long
as such departures do not completely preclude the capacity of the
molecules to form a double-stranded structure. In order for a nucleic
acid molecule to serve as a primer or probe it needs only be sufficiently
complementary in sequence to be able to form a stable double-stranded
structure under the particular solvent and salt concentrations employed.
[0049] The term "specific for (a target sequence)" indicates
that a probe or primer hybridizes under stringent hybridization
conditions only to the target sequence in a sample comprising the
target sequence, and that the hybridization is detectable.
[0050] As used herein, an "isolated" nucleic acid is
one that has been substantially separated or purified away from
other nucleic acid sequences in the cell of the organism in which
the nucleic acid naturally occurs, i.e., other chromosomal and extrachromosomal
DNA and RNA, by conventional nucleic acid-purification methods.
The term also embraces recombinant nucleic acids and chemically
synthesized nucleic acids.
[0051] As used herein, a "substantially homologous" sequence
is a nucleic acid sequence that specifically hybridizes to the complement
of the nucleic acid sequence to which it is being compared, i.e.,
the target sequence, under high stringency conditions. Appropriate
stringency conditions which promote DNA hybridization, for example,
6.0.times. sodium chloride/sodium citrate (SSC) at about 45.degree.
C., followed by a wash of 2.0.times.SSC at 50.degree. C., are known
to those skilled in the art or can be found in Current Protocols
in Molecular Biology, John Wiley & Sons, N.Y., 6.3.1-6.3.6.,
1989. For example, the salt concentration in the wash step can be
selected from a low stringency of about 2.0.times.SSC at 50.degree.
C. to a high stringency of about 0.2.times.SSC at 50.degree. C.
In addition, the temperature in the wash step can be increased from
low stringency conditions at room temperature, about 22.degree.
C., to high stringency conditions at about 65.degree. C. Both temperature
and salt may be varied, or either the temperature or the salt concentration
may be held constant while the other variable is changed. In a preferred
embodiment, a nucleic acid of the present invention will specifically
hybridize to one or more of the nucleic acid molecules set forth
either in SEQ ID NO:1 or SEQ ID NO:2 or complements thereof or fragments
of either under moderately stringent conditions, for example at
about 2.0.times.SSC and about 65.degree. C. In a particularly preferred
embodiment, a nucleic acid of the present invention will specifically
hybridize to one or more of the nucleic acid molecules set forth
either in SEQ ID NO:1 or SEQ ID NO:2 or complements or fragments
of either under high stringency conditions. A nucleic acid of the
present invention that hybridizes to a nucleic acid sequence comprising
SEQ ID NO:1 or to a nucleic acid sequence comprising SEQ ID NO:3
will not necessarily hybridize to a nucleic acid sequence comprising
SEQ ID NO:2 or to a nucleic acid sequence comprising SEQ ID NO:4,
and vice versa.
[0052] In one aspect of the present invention, a preferred marker
nucleic acid molecule of the present invention has the nucleic acid
sequence set forth in SEQ ID NO:1 or in SEQ ID NO:2 or complements
thereof or fragments of either. In another aspect of the present
invention, a preferred marker nucleic acid molecule of the present
invention shares between 80% and 100% or between 90% and 100% sequence
identity with the nucleic acid sequence set forth in SEQ ID NO:1
and SEQ ID NO:2 or complement thereof or fragments of either. In
a further aspect of the present invention, a preferred marker nucleic
acid molecule of the present invention shares between 95% and 100%
sequence identity with the sequence set forth in SEQ ID NO:1 and
SEQ ID NO:2 or complement thereof or fragments of either. SEQ ID
NO:1 and SEQ ID NO:2 may be used as markers in plant breeding methods
to identify the progeny of genetic crosses similar to the methods
described for simple sequence repeat DNA marker analysis, in "DNA
markers: Protocols, Applications, and Overviews, 173-185, Cregan,
et al., eds., Wiley-Liss NY, 1997. The hybridization of the probe
to the target DNA molecule can be detected by any number of methods
known to those skilled in the art, these can include, but are not
limited to, fluorescent tags, radioactive tags, antibody based tags,
and chemiluminescent tags.
[0053] Regarding the amplification of a target nucleic acid sequence
(e.g., by PCR) using a particular amplification primer pair, "stringent
conditions" are conditions that permit the individual primers
in a primer pair to hybridize only to the individual and unique
target nucleic-acid sequence to which each primer, comprising the
corresponding wild-type sequence (or its complement), would bind,
and preferably to produce a unique amplification product, the amplicon,
in a DNA thermal amplification reaction.
[0054] As used herein, the term "transformation" refers
to the transfer of a nucleic acid fragment into the genome of a
host organism such as a host plant, resulting in genetically stable
inheritance. Host plants containing the transformed nucleic acid
fragments are referred to as "transgenic plants".
[0055] As used herein, "amplified DNA" or "amplicon"
refers to the product of nucleic-acid amplification of a target
nucleic acid sequence that is part of a nucleic acid template. For
example, to determine whether the corn plant resulting from a sexual
cross contains transgenic event genomic DNA from the corn plant
MON863 of the present invention, DNA extracted from a corn plant
tissue sample may be subjected to a nucleic acid amplification method
using a primer pair that includes a primer derived from the flanking
sequence in the genome of the plant adjacent to the insertion site
of the inserted heterologous DNA, and a second primer derived from
the inserted heterologous DNA to produce an amplicon that is diagnostic
for the presence of the event DNA. The amplicon is of a length and
has a sequence that is also diagnostic for the event. The amplicon
may range in length from the combined length of the primer pairs
plus one nucleotide base pair, preferably plus about fifty nucleotide
base pairs, more preferably plus about two hundred-fifty nucleotide
base pairs, and even more preferably plus about four hundred-fifty
nucleotide base pairs. Alternatively, a primer pair can be derived
from the flanking sequence on both sides of the inserted DNA so
as to produce an amplicon that includes the entire insert nucleotide
sequence. A member of a primer pair derived from the plant genomic
sequence may be located in a distance from the inserted DNA sequence,
this distance can range from one nucleotide base pair up to about
twenty thousand nucleotide base pairs. The use of the term "amplicon"
specifically excludes primer dimers that may be formed in the DNA
thermal amplification reaction.
[0056] Nucleic-acid amplification can be accomplished by any of
the various nucleic-acid amplification methods known in the art,
including the polymerase chain reaction (PCR). A variety of amplification
methods are known in the art and are described, inter alia, in U.S.
Pat. Nos. 4,683,195 and 4,683,202 and in PCR Protocols: A Guide
to Methods and Applications, ed. Innis et al., Academic Press, San
Diego, 1990. PCR amplification methods have been developed to amplify
up to 22 kb of genomic DNA and up to 42 kb of bacteriophage DNA
(Cheng et al., Proc. Natl. Acad. Sci. USA 91:5695-5699, 1994). These
methods as well as other methods known in the art of DNA amplification
may be used in the practice of the present invention. The sequence
of the heterologous DNA insert or the flanking sequence from the
corn event MON863 can be verified (and corrected if necessary) by
amplifying such sequences from the event using primers derived from
the sequences provided herein followed by standard DNA sequencing
of the PCR amplicon or of the cloned DNA.
[0057] The amplicon produced by these methods may be detected by
a plurality of techniques. One such method is Genetic Bit Analysis
(Nikiforov, et al. Nucleic Acid Res. 22:4167-4175, 1994) where a
DNA oligonucleotide is designed which overlaps both the adjacent
flanking genomic DNA sequence and the inserted DNA sequence. The
oligonucleotide is immobilized in wells of a microwell plate. Following
PCR of the region of interest (using one primer in the inserted
sequence and one in the adjacent flanking genomic sequence), a single-stranded
PCR product can be hybridized to the immobilized oligonucleotide
and serve as a template for a single base extension reaction using
a DNA polymerase and labelled ddNTPs specific for the expected next
base. Readout may be fluorescent or ELISA-based. A signal indicates
presence of the insert/flanking sequence due to successful amplification,
hybridization, and single base extension.
[0058] Another method is the Pyrosequencing technique as described
by Winge (Innov. Pharma. Tech. 00:18-24, 2000). In this method an
oligonucleotide is designed that overlaps the adjacent genomic DNA
and insert DNA junction. The oligonucleotide is hybridized to single-stranded
PCR product from the region of interest (one primer in the inserted
sequence and one in the flanking genomic sequence) and incubated
in the presence of a DNA polymerase, ATP, sulfurylase, luciferase,
apyrase, adenosine 5' phosphosulfate and luciferin. DNTPs are added
individually and the incorporation results in a light signal that
is measured. The light signal indicates the presence of the transgene
insert/flanking sequence due to successful amplification, hybridization,
and single or multi-base extension.
[0059] Fluorescence Polarization as described by Chen, et al.,
(Genome Res. 9: 492-498, 1999) is a method that can be used to detect
the amplicon of the present invention. Using this method an oligonucleotide
is designed which overlaps the genomic flanking and inserted DNA
junction. The oligonucleotide is hybridized to single-stranded PCR
product from the region of interest (one primer in the inserted
DNA and one in the flanking genomic DNA sequence) and incubated
in the presence of a DNA polymerase and a fluorescent-labeled ddNTP.
A single base extension results in incorporation of the ddNTP. Incorporation
can be measured as a change in polarization using a fluorometer.
A change in polarization indicates the presence of the transgene
insert/flanking sequence due to successful amplification, hybridization,
and single base extension.
[0060] Taqman.RTM. (PE Applied Biosystems, Foster City, Calif.)
is described as a method of detecting and quantifying the presence
of a DNA sequence and is fully understood in the instructions provided
by the manufacturer. Briefly, a FRET oligonucleotide probe is designed
which overlaps the genomic flanking and insert DNA junction. The
FRET probe and PCR primers (one primer in the insert DNA sequence
and one in the flanking genomic sequence) are cycled in the presence
of a thermostable polymerase and dNTPs. Hybridization of the FRET
probe results in cleavage and release of the fluorescent moiety
away from the quenching moiety on the FRET probe. A fluorescent
signal indicates the presence of the flanking/transgene insert sequence
due to successful amplification and hybridization.
[0061] Molecular Beacons have been described for use in sequence
detection as described in Tyangi, et al. (Nature Biotech. 14: 303-308,
1996). Briefly, a FRET oligonucleotide probe is designed that overlaps
the flanking genomic and insert DNA junction. The unique structure
of the FRET probe results in it containing secondary structure that
keeps the fluorescent and quenching moieties in close proximity.
The FRET probe and PCR primers (one primer in the insert DNA sequence
and one in the flanking genomic sequence) are cycled in the presence
of a thermostable polymerase and dNTPs. Following successful PCR
amplification, hybridization of the FRET probe to the target sequence
results in the removal of the probe secondary structure and spatial
separation of the fluorescent and quenching moieties. A fluorescent
signal results. The fluorescent signal indicates the presence of
the flanking/transgene insert sequence due to successful amplification
and hybridization, and is diagnostic for the corn event MON863 nucleic
acid in a sample.
[0062] All of the above methods can be modified to determine the
zygosity of a particular sample of nucleic acids derived from a
single source. For example, a corn event MON863 plant which is homozygous
for the event 863 allele contains within its genome two copies of
the event 863 allele characteristic of and diagnostic for the corn
event MON863 genome, and thus when selfed would breed true. Alternatively,
a corn event MON863 homozygous plant can be crossed with another
variety of corn, and the result of that cross would be plants that
were heterozygous for the event MON863 allele. Methods are envisioned
in which one skilled in the art could determine the zygosity of
a particular plant with reference to the event MON863 allele.
[0063] For example, the use of three different primers in an amplification
reaction with corn event MON863 DNA as a template, and in a separate
and parallel amplification reaction with negative control corn DNA
that is not MON863, i.e., that does not contain the inserted DNA
present within MON863 DNA, would result in two different outcomes
depending on the zygosity of the corn DNA containing the corn event
MON863 DNA. Exemplary primers could be selected from the group consisting
of SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:12. Amplification of
non-MON863 DNA with this group of primers would result in primer
pair SEQ ID NO:10 and SEQ ID NO:12 producing a first amplicon corresponding
to the contiguous corn genome sequence into which the PV-ZMIR13
sequence was inserted, that amplified sequence corresponding substantially
to the linked combination of SEQ ID NO:5 and SEQ ID NO:6. This first
amplicon would be expected in a plant that was heterozygous for
the corn event MON863 allele, however, a heterozygote would also
produce a second amplicon corresponding to SEQ ID NO:3 from the
extension of the primer pair corresponding to SEQ ID NO:9 and SEQ
ID NO:10. A corn plant containing DNA that was homozygous for the
MON863 allele would only produce the second amplicon.
[0064] Similarly, a third amplicon would be produced from a thermal
amplification reaction that used the primers SEQ ID NO:10, SEQ ID
NO:11, and SEQ ID NO:12 with template DNA from a MON863 corn plant,
this third amplicon corresponding to SEQ ID NO:4. This third amplicon
would be the only amplicon produced using this particular combination
of primers and template DNA if the plant was homozygous for the
MON863 allele, however, heterozygote template DNA would result in
the amplification of the first and the third amplicons, and non-MON863
template DNA would result in the amplification of only the first
amplicon.
[0065] Herein, the inventors have determined as judged by molecular
characterization that corn event MON863 contains a primary functional
insert containing a significant portion of the transformation plasmid,
PV-ZMIR13. This segment is detectable and diagnostic for the event
MON863 nucleic acid sequences in a sample, in particular in plants
that have been selfed since the origination of the MON863 event.
[0066] There are many methods for transforming the Cry3Bb nucleic
acid molecules into plant cells such as maize plant cells to produce
a desired event such as MON863. Suitable methods are believed to
include virtually any methods by which nucleic acid molecules may
be introduced into the cells, such as by Agrobacterium infection
or direct delivery of nucleic acid molecules that may include PEG-mediated
transformation, electroporation and acceleration of DNA coated particles,
etc. (Pottykus, Ann. Rev. Plant Physiol. Plant Mol. Biol. 42:205-225,
1991; Vasil, Plant Mol. Biol. 25: 925-937, 1994). For example, electroporation
has been used to transform Zea mays protoplasts (Fromm et al., Nature
312:791-793, 1986). In general, the following are four most commonly
used general methods for delivering a gene into cells: (1) chemical
methods (Graham and van der Eb, Virology, 54:536-539, 1973); (2)
physical methods such as microinjection (Capecchi, Cell 22:479-488,
1980), electroporation (Wong and Neumann, Biochem. Biophys. Res.
Commun. 107:584-587, 1982; Fromm et al., Proc. Natl. Acad. Sci.
(USA) 82:5824-5828, 1985; U.S. Pat. No. 5,384,253); and the gene
gun (Johnston and Tang, Methods Cell Biol. 43:353-365, 1994); (3)
viral vectors (Clapp, Clin. Perinatol. 20:155-168, 1993; Lu et al.,
J. Exp. Med. 178:2089-2096, 1993; Eglitis and Anderson, Biotechniques
6:608-614, 1988); and (4) receptor-mediated mechanisms (Curiel et
al., Hum. Gen. Ther. 3: 147-154, 1992; Wagner et al., Proc. Natl.
Acad. Sci. (USA) 89: 6099-6103, 1992).
[0067] Transformation of plant protoplasts can be achieved using
methods based on calcium phosphate precipitation, polyethylene glycol
treatment, electroporation, and combinations of these treatments.
See for example (Potrykus et al., Mol. Gen. Genet., 205:193-200,
1986; Lorz et al., Mol. Gen. Genet., 199:178, 1985; Fromm et al.,
Nature, 319:791, 1986; Uchimiya et al., Mol. Gen. Genet.:204:204,
1986; Callis et al., Genes and Development, 1183, 1987; Marcotte
et al., Nature, 335:454, 1988). Application of these systems to
different plant strains depends upon the ability to regenerate that
particular plant strain from protoplasts. Among them are the methods
for corn (U.S. Pat. No. 5,569,834, U.S. Pat. No. 5,416,011; McCabe
et al., Biotechnology 6:923, 1988; Christou et al., Plant Physiol.,
87:671-674, 1988). Illustrative methods for the regeneration of
cereals from protoplasts are also described (Fujimura et al., Plant
Tissue Culture Letters, 2:74, 1985; Toriyama et al., Theor. Appl.
Genet. 205:34, 1986; Yamada et al., Plant Cell Rep. 4: 85, 1986;
Abdullah et al., Biotechnology, 4:1087, 1986).
[0068] A transgenic plant such as a transgenic corn MON863 plant
formed using transformation methods typically contains a single
added Cry3Bb gene on one chromosome. Such a transgenic plant can
be referred to as being heterozygous for the added Cry3Bb gene.
More preferred is a transgenic plant that is homozygous for the
added Cry3Bb gene; i.e., a transgenic plant that contains two added
Cry3Bb genes, one gene at the same locus on each chromosome of a
chromosome pair. A homozygous transgenic plant can be obtained by
sexually mating (selfing) an independent segregated transgenic plant
that contains a single added Cry3Bb gene, germinating some of the
seeds produced and analyzing the resulting plants produced for the
Cry3Bb gene.
[0069] It is understood that two different transgenic plants can
also be mated to produce offspring that contain two independently
segregating added Cry3Bb genes. Selfing of appropriate progeny can
produce plants that are homozygous for both added Cry3Bb genes that
encode Cry3Bb polypeptides. Backcrossing to a parental plant and
out-crossing with a non-transgenic plant are also contemplated,
as is vegetative propagation.
[0070] Specifically, a method for producing a corn plant that is
resistant to coleopteran insect infestation may be conducted with
the following steps: 1) sexually crossing a first corn plant grown
from the corn seed event MON863 comprising a DNA molecule selected
from the group consisting of SEQ ID NO: 1, SEQ ID NO:2, SEQ ID NO:3,
SEQ ID NO:4 and SEQ ID NO:20 that confers resistance to coleopteran
insect infestation, and a second corn plant that lacks the resistance
to coleopteran insect infestation, thereby producing a plurality
of first progeny plants; 2) selecting a first progeny plant that
is resistant to coleopteran insect infestation; 3) selfing said
first progeny plant, thereby producing a plurality of second progeny
plants; and 4) selecting from said second progeny plants a plant
resistant to coleopteran insect infestation. The first progeny plant
that is resistant to coleopteran insect infestation or the second
progeny plant that is resistant to coleopteran insect infestation
may be backcrossed to the second corn plant or a third corn plant
resulting in a corn plant that is resistant to coleopteran insect
damage infestation.
[0071] The regeneration, development, and cultivation of plants
such as the MON863 plants from transformants or from various transformed
explants are well known in the art (Weissbach and Weissbach, In:
Methods for Plant Molecular Biology, Eds., Academic Press, Inc.
San Diego, Calif., 1988). This regeneration and growth process may
typically include the steps of selection of transformed cells containing
exogenous Cry3Bb genes, culturing those individualized cells through
the usual stages of embryonic development through the rooted plantlet
stage. Transgenic embryos and seeds are similarly regenerated. The
resulting transgenic rooted shoots are thereafter planted in an
appropriate plant growth medium such as soil.
[0072] The regeneration of plants containing the foreign, exogenous
gene that encodes a protein of interest is well known in the art.
As described in the present invention, the regenerated plants such
as the regenerated MON863 plants that contain the Cry3Bb nucleic
acids, either wild type or chemically synthesized, that encode for
the Cry3Bb proteins, may be preferably self-pollinated to provide
homozygous transgenic maize plants, as discussed before. Otherwise,
pollen obtained from the regenerated maize plants may be crossed
to seed-grown plants of agronomically important lines. Conversely,
pollen from plants of these important lines is used to pollinate
regenerated plants. A transgenic MON863 plant of the present invention
may be cultivated using methods well known to one skilled in the
art.
[0073] There are a variety of methods for the regeneration of plants
from plant tissue. The particular method of regeneration will depend
on the starting plant tissue and the particular plant species to
be regenerated. Transformation of monocot plants using electroporation,
particle bombardment, and Agrobacterium has also been reported.
Transformation and plant regeneration have been achieved in many
monocot plants that include maize, asparagus, barley and wheat,
etc. (Bytebier et al., Proc. Natl. Acad. Sci. USA 84:5345, 1987;
Wan and Lemaux, Plant Physiol 104:37, 1994; Rhodes et al., Science
240: 204, 1988; Gordon-Kamm et al., Plant Cell, 2:603, 1990; Fromm
et al., Bio/Technology 8:833, 1990; Armstrong et al., Crop Science
35:550-557, 1995; Vasil et al., Bio/Technology 10:667, 1992; U.S.
Pat. No. 5,631,152).
[0074] In addition to the above discussed procedures, practitioners
are familiar with the standard resource materials which describe
specific conditions and procedures for the construction, manipulation
and isolation of macromolecules (e.g., DNA molecules, plasmids,
etc.), generation of recombinant organisms and the screening and
isolating of clones (see, for example, Sambrook et al., Molecular
Cloning: A Laboratory Manual, Cold Spring Harbor Press, 1989; Mailga
et al., Methods in Plant Molecular Biology, Cold Spring Harbor Press,
1995; Birren et al., Genome Analysis: Analyzing DNA, 1, Cold Spring
Harbor, N.Y., 1997).
[0075] DNA detection kits can be developed using the compositions
disclosed herein and the methods well known in the art of DNA detection.
The kits are useful for identification of corn event MON863 DNA
in a sample and can be applied to methods for breeding corn plants
containing the MON863 DNA. The kits contain one or more DNA sequences
comprising at least 11 contiguous nucleotides homologous or complementary
to sequences selected from the group consisting of SEQ ID NO:1,
SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6,
SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11,
SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16,
SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:20, SEQ ID NO:21,
and complements thereof. These DNA sequences can be used in DNA
amplification reactions or as probes in a DNA hybridization method.
[0076] The following examples are included to demonstrate examples
of certain preferred embodiments of the invention. It should be
appreciated by those of skill in the art that the techniques disclosed
in the examples that follow represent approaches the inventors have
found function well in the practice of the invention, and thus can
be considered to constitute examples of preferred modes for its
practice. However, those of skill in the art should, in light of
the present disclosure, appreciate that many changes can be made
in the specific embodiments that are disclosed and still obtain
a like or similar result without departing from the spirit and scope
of the invention.
EXAMPLES
Example 1
Isolation and Characterization of the DNA Sequences Flanking the
MON863 Insertion Event
[0077] Corn event MON863 was generated through particle acceleration
technology using a 4.7-Kb agarose gel-isolated Mlu I restriction
fragment from the plasmid vector PV-ZMIR13 (pMON25097, FIG. 1).
The plant expression vector pMON25097 contains a first expression
cassette comprising a non-naturally occurring CaMV35S AS4 promoter
sequence (P-CaMV.AS4, SEQ ID NO:17) operably connected to a wheat
chlorophyll A/B binding protein untranslated leader sequence (L-Ta.hcb1,
SEQ ID NO:18) operably connected to a rice actin intron sequence
(I-Os.Act1, SEQ ID NO:19) operably connected to a non-naturally
occurring sequence encoding Cry3Bb variant protein (SEQ ID NO:20)
operably connected to a wheat heat shock Hsp17 transcription termination
and polyadenylation sequence (T-Ta.Hsp17, SEQ ID NO:21). The plant
expression vector pMON25097 contains a second expression cassette
linked to the Cry3Bb expression cassette that confers paromomycin
resistance to transformed plant tissue (i.e. the 3' end of the cry3Bb
expression cassette is linked to the 5' end of the second expression
cassette conferring paromomycin resistance). This resistance cassette
consists of an enhanced CaMV35S promoter sequence (U.S. Pat. No.
5,164,316) that is operably connected to a neomycin phosphotransferase
coding sequence (U.S. Pat. No. 5,569,834) that is operably connected
to a nopaline synthase transcription termination and polyadenylation
sequence (Fraley et al. Proc. Natl. Acad. Sci. USA 80:4803-4807,
1983). Transgenic corn plants resistant to paromomycin were derived
essentially as described in U.S. Pat. No. 5,424,412.
[0078] Molecular characterization of the insert in the corn event
MON863 demonstrated that one copy of the DNA fragment used for transformation
is present in the corn event MON863. In order to develop event-specific
PCR identification methods, the sequences of corn DNA flanking the
5' and 3' ends of the insert in the corn event MON863 were determined
using GenomeWalker.TM. technology (Clontech Laboratories, Inc.)
in accordance with the manufacturer's instructions. The GenomeWalker.TM.
method involves first completely digesting purified corn MON863
DNA with different restriction enzymes provided in the GenomeWalker.TM.
kit that leave blunt ends. Next, the purified blunt-ended genomic
DNA fragments are ligated to GenomeWalker.TM. Adaptors comprising
known nucleic acid fragments. Each ligation is then amplified in
a first PCR reaction using an outer adaptor primer, SEQ ID NO:22
(5'-GTAATACGACTCACTATAGGGC-3') provided by GenomeWalker.TM. and
an outer, gene-specific primer (SEQ ID NO:13, 5'-GAACGTCTTCTTTTTCCACGATGCTCC-3',
and SEQ ID NO:15, 5'-GCGAGTCTGATGAGACATCTCTGTAT-3', for the 5' and
3' ends of the transgene insert, respectively). The first PCR product
mixture is then diluted and used as a template for a secondary or
nested PCR with the nested adaptor primer, SEQ ID NO:23 (5'-ACTATAGGGCACGCGTGGT-3')
provided by GenomeWalker.TM. and a nested gene-specific primer (SEQ
ID NO:14, 5'-TCGGCAGAGGCATCTTGAATGATAGC-3', and SEQ ID NO:16, 5'-AATTTGGTTGATGTGTGTGCGAGTTCT-3',
for the 5' and 3' ends of the transgene insert, respectively). The
secondary PCR product, which begins with the known gene-specific
sequences and extends into the unknown adjacent genomic DNA, can
then be sequenced using methods well known in the art. Once the
flanking corn genomic sequences were determined, PCR assays capable
of detecting the presence of corn plant PV-ZMIR13 (MON863) DNA in
a sample were developed.
[0079] Following this procedure, the nucleotide sequence as set
forth in SEQ ID NO:5 was characterized as the corn genome sequence
that is immediately adjacent to and upstream of the arbitrarily
assigned 5' end of the pMON25097 DNA fragment that was inserted
into the corn genome resulting in the construction and isolation
of transgenic corn event MON863. One skilled in the art, or even
one of ordinary skill in the art, would realize that additional
nucleotide sequence information can readily be obtained that is
even more distal from the junction sequence as set forth in SEQ
ID NO:1 but still within the corn genome than the present 242 nucleotides
exemplified herein in SEQ ID NO:5, and from nucleotide position
267 through nucleotide position 508 as set forth in SEQ ID NO:3.
Also, the nucleotide sequence as set forth in SEQ ID NO:6 was characterized
as the corn genome sequence that is immediately adjacent to and
downstream of the arbitrarily assigned 3' end of the pMON25097 DNA
fragment that was inserted into the corn genome resulting in the
construction and isolation of transgenic corn event MON863. One
skilled in the art will also realize that additional nucleotide
sequence information can readily be obtained that is even more distal
from the junction sequence as set forth in SEQ ID NO:2 but still
within the corn genome than the present 224 nucleotides exemplified
herein in SEQ ID NO:6, and from nucleotide position 361 through
nucleotide position 584 as set forth in SEQ ID NO:4.
Example 2
Detection of the Presence of MON863 DNA in a Sample
[0080] The following provides a non-limiting example of the PCR
assays developed to detect the presence of the MON863 DNA in a sample.
[0081] DNA was extracted from approximately 100 mg of ground grain
tissue using Qiagen's Dneasy Plant Mini Kit (catalog # 68163, Valencia,
Calif.) according to the manufacturer's recommended protocol with
one exception. The grain used was processed prior to extraction
in a -80.degree. C. freezer, and not ground under liquid nitrogen
using a mortar and pestle immediately prior to extraction. DNA quantitation
was conducted using methods well-known in the art, a Hoefer DNA
Quant 200 Fluorometer, and Boehringer Mannheim (Indianapolis, Ind.)
molecular size marker IX as a DNA calibration standard.
[0082] PCR analysis of the genomic DNA sequences flanking the 5'
end of the insert in MON863 was performed using one primer (primer
A) derived from the 5' genomic flanking sequence (SEQ ID NO:9, 5'-GTCTTGCGAAGGATAGTGGGAT-3')
paired with a second primer (primer B) located near the 5' end of
the inserted DNA in the 35S promoter (SEQ ID NO:10, 5'-CATATGACATAAGCGCTCTTGG-3'),
covering a 508-bp region. The PCR analysis for genomic DNA sequences
flanking the 3' end of the MON863 insert was conducted using one
primer (primer D) derived from the 3' genomic flanking sequence
(SEQ ID NO:12, 5'-AGACTCTATGCTCTGCTCATAT-3') paired with a second
primer (primer C) located in the tahsp17 polyadenylation sequence
near the 3' end of the insert spanning a 584-bp region (SEQ ID NO:11,
5'-CTGATCATTGGTGCTGAGTCCTT-3') (FIG. 2). The PCR analyses were conducted
using 50 ng of the corn event MON863 genomic DNA or a MON846 non-transgenic
genomic DNA template in a 50 .mu.L reaction volume containing a
final concentration of 1.5 mM Mg.sup.2+, 0.4 .mu.M of each primer,
200 .mu.M each dNTP, and 2.5 units of Taq DNA polymerase. The reactions
were performed under the following cycling conditions: 1 cycle at
94.degree. C. for 3 minutes; 38 cycles of 94.degree. C. for 30 seconds,
60.degree. C. for 30 seconds, 72.degree. C. for 1.5 minutes; 1 cycle
at 72.degree. C. for 10 minutes.
[0083] The PCR products (20 .mu.L) of the expected sizes representing
the genomic sequence flanking the 5' and 3' ends of the insert were
isolated by gel electrophoresis on a 2.0% agarose gel at 60 V for
.about.1 hour and visualized by ethidium bromide staining. The PCR
fragments representing the 5' and 3' flanking sequences were excised
from the gel and purified using the QIAquick Gel Extraction Kit
(Qiagen, catalog # 28704) following the procedure supplied by the
manufacturer. The purified PCR products were then sequenced with
the initial PCR primers using dye-terminator chemistry.
[0084] The control reactions containing no template as well as
the reactions containing non-transgenic corn DNA did not generate
a PCR product with either primer set, as expected. PCR analysis
of the corn rootworm event MON863 DNA generated the expected size
products of 508 bp representing the 5' flanking sequence (SEQ ID
NO:3) when using primers A and B having SEQ ID NOs: 9 and 10 and
584 bp representing the 3' flanking sequence (SEQ ID NO:4) when
using primers D and C having SEQ ID NOs: 11 and 12.
[0085] Sequence data indicated that the 5' amplicon, i.e., SEQ
ID NO:3, consisted of 266 bp of the 5' end of the 35S promoter at
the 5' end of the insert followed by 242 bp of corn genomic flanking
DNA. Sequence data indicated that the 3' amplicon, i.e., SEQ ID
NO:4, consisted of 360 bp of the tahsp17 3' polyadenylation sequence
which defines the 3' end of the insert, immediately followed by
224 bp of corn genomic flanking DNA.
[0086] Agronomically and commercially important products and/or
compositions of matter including but not limited to animal feed,
commodities, and corn products and by-products that are intended
for use as food for human consumption or for use in compositions
that are intended for human consumption including but not limited
to corn flour, corn meal, corn syrup, corn oil, corn starch, popcorn,
corn cakes, cereals containing corn and corn by-products, and the
like are intended to be within the scope of the present invention
if these products and compositions of matter contain detectable
amounts of the nucleotide sequences set forth herein as being diagnostic
for the corn event MON863.
[0087] Seed comprising the MON863 corn event have been deposited
by the Applicant with American Type Culture Collection (ATCC), 10801
University Boulevard, Manassas, Va., USA ZIP 20110-2209 on Oct.
17, 2000. The ATCC provided the Applicant with a deposit receipt,
assigning the ATCC Deposit Accession No. PTA-2605 to the corn Zea
mays event MON863 PV-ZMIR13.
[0088] Those of skill in the art, in light of these examples, should
appreciate that many changes can be made to the foregoing assays
to detect DNA derived from corn event MON863 in a sample. For example,
a primer set comprising one primer complementary to corn genome
DNA and another primer complementary to sequences within the insert
are envisioned. Furthermore, any of various hybridization assays
described earlier using DNA probes complementary to the novel nucleic
acid sequences located at transgene/genome junctions are envisioned
as well.
[0089] Having illustrated and described the principles of the present
invention, it should be apparent to persons skilled in the art that
the invention can be modified in arrangement and detail without
departing from such principles. We claim all modifications that
are within the spirit and scope of the appended claims.
[0090] All publications and published patent documents cited in
this specification are incorporated herein by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by reference.
Sequence CWU 1
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