Worm Breeder's Gazette 13(4): 42 (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.

dx5 and Various Aspects of Gonadogenesis.

Marc Ginsburg, Eric Lambie

Department of Biological Sciences, Dartmouth College, Hanover NH 03755.

  One lucky day, we found a UV-induced mutation ( dx5 )that maps to IR and has
strikingly obvious gonadogenesis defects. First, the dx5 / dx5 progeny of a dx5
/+hermaphrodite often have proximal germline proliferation in one (and sometimes
both) of the gonad arms. Despite such an abnormality, all of these animals are fertile.
This phenotype is reminiscent of that seen in lin-12 (0)mutants, in which the anchor
cell(s) induce proximal germline proliferation. However, dx5 animals do not exhibit
either the two-anchor-cell phenotype or vulva morphogenesis defects characteristic of
lin-12 (0)mutants.
  To determine whether the anchor cell is responsible for inducing proximal
proliferation in dx5 animals, we tested the effect of lin-12 ( n302 ),which prevents
specification of the anchor cell fate. None of 20 Unc progeny of dx5 unc-75 ( e950 )/++ I;
lin-12 ( n302 )III hermaphrodites had proximal proliferation. 19/49 Unc progeny of
dx5 unc-75 ( e950 )/++ controls had proximal proliferation. This strongly suggests that
the anchor cell is the culprit; however, we'll have to do some laser ablation experiments
to be certain.
  The second glaringly obvious effect of dx5 is seen among the progeny of dx5 / dx5
homozygotes. These animals have very small gonads and are usually vulvaless
(presumably due to lack of an anchor cell). More detailed inspection will be necessary
to determine exactly which cell divisions have gone awry.
  We are optimistic that we can make good progress towards determining the
normal function of the gene defined by dx5 .For one thing, the dx5 mutation is
temperature sensitive, which should permit the isolation of additional alleles by clonal
noncomplementation screening. Another good thing is that dx5 maps very close to
lin-11 (probably to the left); this region is fairly well-covered on the physical map by
cosmids and YACs.