Worm Breeder's Gazette 8(3): 62
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.
Four yolk proteins have been identified in C. elegans: Two closely related proteins of approximately 170,000 daltons (yp170A and yp170B), and two other polypeptides of 115,000 daltons (yp115) and 88,000 daltons (yp88) (Sharrock, 1983. Develo. Biol, 96, 182-188). yp115 and yp88 have been shown to be derived from a 180,000 dalton precursor ( Sharrock, 1984, J. Mol. Biol 174, 419-431). We recently have shown that yp170A and yp170B are encoded by a five gene family (YP1-5) ( Blumenthal et al.. 1984, J. Mol. Biol. 174, 1-18). We have now cloned a developmentally-regulated gene that, based on the timing of expression, size and abundance of the mRNA and finally, hybrid-arreat translation experiments, encodes the 180.000 dalton precursor to yp115 and yp88 . The gene (YP6) was cloned from a C. rary by selecting abundantly expressed sequences that were adult specific but did not hybridize to YP1-5. Genomic clones were selected from John Karn's lambda1059 library. Based on genomic Southern blots the precursor to yp115 and yp88 is encoded by a single-copy gene. It is about 5.5 kb long and hybridizes to a 5.2 kb RNA. YP6 RNA is as abundant in adult hermaphrodites as is the RNA from the YP1-5 gene family but, like YP1-5 RNA, YP6 RNA is not detectable in larvae or adult males. Based on DNA sequence comparison YP6 is distantly related to the YP1- 5 genes suggesting that all of the yolk protein genes evolved from a common ancestor.