Worm Breeder's Gazette 14(4): 42 (October 1, 1996)

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.


Andreas Eizinger, Kwang-Zin Lee, Carola Weise, Isabel Schlak, Ralf J. Sommer

Max-Planck Institut fuer Entwicklungsbiologie, Abteilung Zellbiologie, Spemannstrasse 35, 72076 Tuebingen, Germany.

To study the molecular mechanisms underlying changes in cell fate
specification during evolution, we started a genetic analysis of vulva
development in Pristionchus. Pristionchus has a four day life-cycle, is
easily cultured on OP50 and has six chromosomes by DAPI staining. In a
small genetic pilot screen, more than 50 morphological mutants,
representing the typical spectrum known from Caenorhabditis, have been
isolated (Fund. Appl. Nemat. 19, 511-522).
        In a large screen of 40 000 gametes we have isolated 49 vulval
defective mutants. Based on phenotype we can distinguish four groups of
mutants, as well as two mutants with a unique phenotype (this includes
the previously described ped-5 mutant).
Group I: These mutants are lineage defective. In some mutants, P6.p
adopts a 2o or hybrid fate instead of the 1o fate. However, cell
ablation experiments indicate that these mutants are not lin-12(d)-like,
as an AC is present and no differentiation was seen after
Group II: These mutants have phenotypes similar to the previously
described ped-6 mutant. Altogether 9 mutants have been isolated. Cell
lineage analysis and cell ablation experiments indicate a different
penetrance of individual mutants. Characterization is ongoing.
Group III: These mutants are similar to the previously describedped-4
mutant. This group is surprisingly big, containing 12 mutants. Cell
ablation experiments suggest that different subgroups of mutants can be
distinguished. In some mutants only P(7,8).p, in others also P(5,6).p
can differentiate after ablation of the gonad. However, we can not rule
out, that these differences are based on the different penetrance of
allelic mutations. Characterization is ongoing.
Group IV: Mutants exhibiting a vulvaless-phenotype. Altogether, 17
mutants have been isolated that vary dramatically in penetrance. As in
C. elegans, two types of vulvaless-phenotypes can be distinguished: In
one group, VPCs adopt the 3o fate as in AC-ablated animals, in the other
group, VPCs undergo programmed cell death as the more anterior and
posterior epidermal cells of Pristionchus.