Worm Breeder's Gazette 13(4): 84b (October 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.

Defining Sequences That Rescue vab-8, and Extra Vulval Blips in vab-8.

Ming-shiu Hung, Sharon Sokol, Jeff Way

Dept. of Biology, Nelson Labs, Rutgers University, Piscataway NJ 08855.

  We have identified a 4.8 kb DNA fragment from the cosmid C35G11 that rescues
vab-8 ( e1017 )upon microinjection. This fragment lies about 5 kb from the 3' end of
myo-3 .We have begun sequencing this region, but have not yet identified a vab-8 open
reading frame or any relationships to known DNA or protein sequences. vab-8 ( e1017
)mutant animals occasionally show secondary vulval protrusions (Way et al., 1992).
Generation of the protrusions appears to be independent of the anchor cell. The second
protrusion is always located posterior to the vulva, and often rather far from the anchor
cell. lin-3 ( e1417 ); vab-8 double mutant animals still sometimes show two
protrusions. Also, 40% of lin-9 ( n112 ); vab-8 double mutant animals show ectopic
vulval blips, compared to 12% of lin-9 (+); vab-8 ( e1017 )animals. (We are currently
constructing vab-8 doubles with lin-8 and let-60 .)Together these results suggest that
the secondary vulval blips seen in e1017 are due to a defect in the tertiary
fate-promoting activity from the hypodermis. It is possible that this defect is an
indirect (and unprofound) consequence of the CAN cell migration defect, which causes
a defect in excretion ultimately causing the posterior half of the body to wither. The
posterior part of the body might simply be generally impaired, so that the hypodermal
signal to the Pn.p cells is poorly transmitted.