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2002
LSU-HHMI Summer Undergraduate Research Program |
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 Taylor
S. Gwin (John C. Larkin, LSU Dept. of Biological Sciences)
Do T-DNA insertions in the Calreticulin gene cause a mutant
floral phenotype in Arabidopsis thaliana?
This summer I continued working on a project that was started
in the summer of 2001. I started with Arabidopsis thaliana plants
that were heterozygous for the siamese-2 mutation (sim-2), a
mutation affecting trichomes, and had insertions of T-DNA (plant
line from Martin Hülskamp) that contained a kanamycin resistant
gene. After crossing the plants with the wild-type plants of
the Columbia ecotype (col), the F2 population segregated for
two T-DNA insertions. T-DNA insertions can cause mutations by
insertion into a gene. We would like to know whether either
of the insertions in the original line might be the cause of
the sim-2 mutant phenotype, and whether either of the insertions
might be the cause of the flower phenotype. The matured plants
also segregated for a flower phenotype (deformed carpels). Jason
Walker in the Larkin lab showed that one of the insertions is
located in the calreticulin gene (CRT), which is located on
a different chromosome than sim. I am particularly interested
in whether this specific CRT insert is the cause of the flower
phenotype. The original line segregated 15:1 kanamycin resistant
to kanamycin sensitive when planted on MS salt plates containing
kanamycin. Several series of PCRs yielded no results to confirm
an insert in CRT. However, the latest series of PCRs have shown
that there is in fact an insertion immediately downstream of
the CRT gene. I am currently trying to finalize establishing
markers so that I can test the F2 families for the CRT insert.
There is also a GUS staining pattern of roots, stipules, trichomes,
and flowers segregating in the original sim-2 population. I
am also working on GUS staining of a few families of the F2
population that did not segregate for the siamese mutation to
determine if the GUS pattern is segregating independent of the
siamese mutation.
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