Worm Breeder's Gazette 9(2): 94

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.

Some Surprising Sexual Suppression by Morphogenetic Mab Mutations

J. Hodgkin

Mutations of the gene tra-3 IV cause partial masculinization of XX 
animals.  A total of 42 extragenic suppressors of tra-3 have been 
isolated and analyzed (see WBG 8-2: 46; Genetics 111: 287).  Most of 
these cause feminization of XX or XO animals when crossed into a tra-3(
+) background.  These feminizing suppressors are all mutations of sex-
determining genes: gain-of-function alleles of tra-1 (11 alleles) or 
tra-2 (one allele), or loss-of-function alleles of fem-1 (4 alleles), 
fem-2 (4 alleles) or fem-3 (18 alleles).
The remaining suppressors are recessive weak suppressors without 
obvious feminizing effects.  They identify four new 
genes:
1) sup(e1992) IV maps between unc-30 and tra-3; ts sterile phenotype.
2) sup(e2042) IV maps between dpy-20 and unc-30; no other phenotype. 
3) egl-48(e1952) II is tightly linked to sqt-3; XX animals Egl-4) 
008) I is close to bli-3; XO animals Mab.
The last suppressor, e2008, has a 'morphogenetic Mab' (male abnormal)
phenotype; mab-11 XO males have swollen bursae, reduced fans and 
shortened rays.  Nevertheless, all male structures (e.g.  copulatory 
spicules) are present and the abnormal males can sometimes mate 
successfully.  Mab-11 XX hermaphrodites have swollen vulvae, and are 
sometimes Egl.  These phenotypes are very similar to those of some 
other mab mutations, particularly mab-1 alleles.  A double mutant, mab-
1(e1228); onstructed and found to show 
similar suppression to mab-11.  This makes it likely that mab-11(e2008)
is a pleiotropic single mutation, rather than a double mutant.  Both 
amber (e1107) and non-amber (e1767) alleles of tra-3 are suppressed by 
mab-11.  Also, tra-2(e1209) (a weak tra-2 allele with a phenotype 
similar to tra-3) is partly suppressed by mab-11.The egl-48 suppressor 
may be related to mab-11 and mab-1, in that egl-48 XO males sometimes 
have swollen bursae, and the Egl phenotype in the XX hermaphrodite 
seems to result from a vulval morphogenesis defect.  Several other mab 
mutations affect morphogenesis (as opposed to lineage) of the bursa, 
and sometimes of the vulva too: mab-4, mab-7, 
ere tested for the ability to 
suppress tra-3; none of them had any effect (nor did the 'lineage 
mabs', mab-3 and mab-9).These suppression effects are minor, but 
striking.  I don't have any attractive explanations at the moment.