Worm Breeder's Gazette 13(3): 26 (June 1, 1994)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.


Bijan Etemad-Moghadam, Kenneth Kemphues

Cornell University, Ithaca New York.

par-3 is a maternally acting gene that is necessary for establishing normal asymmetry of the early C.elegans embryo (Kemphues et. al, Cell, 52, 311-320). The progeny from par-3 homozygotes exhibit several defects during the first cell cycles: the first cleavage is equal and symmetric, and subsequent cleavages show alteration in timing and orientation. Embryos from par-3 homozygous mothers also fail to localize P granules. The resulting embryos arrest as amorphous balls of cells.

As a first step towards learning about the role of par-3 at the molecular level, we started cloning the gene. We mapped par-3 between daf-4 and sma-4 on LGIII, within .05 mu of daf-4 ,which had previously been placed on the physical map. We obtained transformants that rescued the mutant phenotype with a cosmid just to the right of daf-4 , F54E7 .Subsequently, the genomic region of rescuing activity was narrowed down to a 12.1 Kb fragment of F54E7 .

A Northern probed with the 12.1Kb fragment from F54E7 showed a 5Kb maternally-enriched transcript. cDNAs corresponding to this message were isolated from Bob Barstead's cDNA library. Northern blots probed with one of these cDNAs detected transcripts of altered mobility associated with two mutant par-3 alleles ( lw30 and zu163 ).

We have sequenced the longest cDNA (4.4Kb), and no interpretable homologies have been detected in the database. We are currently raising polyclonal antibodies against different parts of the par-3 gene product.