Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 50pg1
PROGRESS TOWARD CLONING THE ARABIDOPSIS DET2 GENE.
Punita Nagpal, Veronique Vitart and Joanne Chory. Plant Biology
Laboratory, The Salk Institute, San Diego, CA 92186-5800.
DET2 is a genetic locus involved in light-mediated early
seedling development in Arabidopsis thaliana. Mutations in the
DET2 gene are recessive and pleiotropic. When grown in the dark,
det2 mutants display many characteristics (in morphology and
gene expression) that are light-mediated in the wild-type.
However, det2 mutants do not initiate the chloroplast
developmental program in the dark and thus allow separation of
two downstream light-regulated responses (gene expression and
morphology) from a third, the development of chloroplasts. In
addition to its role in de-etiolation, DET2 also appears to be
involved in later stages of vegetative growth as det2 mutants
have a prolonged vegetative phase, are late-flowering and show
delayed leaf senescence. In our efforts to study the molecular
mechanisms of signal transduction, DET2 has been mapped to
chromosome 2 and chromosome walking experiments have allowed us
to localize it to a 150 kb YAC. The experiments to delineate the
gene further by walking across the YAC genetically with cosmid
and lambda clones are in progress. Cosmid clones are being used
to transform det2/det2 mutants and test complementation and also
to screen a cDNA library made from etiolated wild-type tissue.
In parallel, we have used these inserts to map a genomic
rearrangement that has occurred in a new promising det2 allele
obtained after fast-neutron irradiation. Our most recent
progress toward identifying the gene will be presented.
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