Worm Breeder's Gazette 13(5): 51 (February 1, 1995)
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.
HHMI and Division of Biology, Caltech, Pasadena, CA 91125
We have previously described the isolation of an egg-laying defective mutant with an abnormal contact between the anchor cell and the vulval precursor cells (WBG 13:3). L3 hermaphrodites homozygous for the sy275 mutation have an abnormal contact between the anchor cell and P6.pap and P6.ppa, i.e., the anchor cell fails to invaginate between the P6.pap and P6.ppa and is often observe on top of the two cells. In mid-L4 hermaphrodites the connection between the uterus and the vulva appears obstructed suggesting that the connection between these two structures is disrupted in this mutant. Hermaphrodites with sy275 in trans to the translocation mnT11 (used as a deficiency, see Herman et. al. Genetics 1982) are egg-laying defective and their brood size is decreased by ~10 fold. In addition, approximately 5percent of the animals are sterile. Other evidence suggesting that sy275 is not a complete loss-of-function allele is that 5percent of sy275 hermaphrodites grown at 25 C are sterile (n=275). We are presently, conducting a non-complementation screen to identify additional alleles. We had previously reported that sy275 males are mating competent, however, quantitative mating experiments indicate that only 30percent of the males tested were able to sire cross progeny (n=50). Examination of sy275 males with Nomarski optics suggests that there may be two linker cell specific defects. In about 30percent of the adult males examined the linker cell had not migrated more than 1/2 way down the ventral side of the animal. Interestingly, the intestines of these worms were completely distended and full of bacteria suggesting that the animals were unable to defecate. In approximately another 30percent of the adult males examined ectopic sperm were present in the body cavity. Ectopic sperm were only observed in mated males but not in virgin adult males. Anatomical observation suggests that in about 30percent of late L4 or young adult males the linker cell, while it has migrated into the tail, has not attached to the proctodeum properly. Thus, sy275 disrupts two analogous cell attachments - the anchor cell to vulva and linker cell to proctodeum.