Worm Breeder's Gazette 9(3): 50

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.

Suppressors of her-1(n695sd)

J. Plenefisch and B. Meyer

Mutations which suppress her-l(n695sd)V are likely to be involved in 
the processes of sex determination or dosage compensation. n695 causes 
an incomplete masculinization of XX animals; homozygotes are uniformly 
egg laying defective (Egl) and approximately 30% display further 
variable sexual transformation of normally hermaphrodite tail 
structures into male-like structures (C. Trent). We have isolated two 
extragenic suppressors of n695 (y11 and y12) which result in the 
following phenotypes: n695; sup animals never display pseudomale tails 
and less than 10% are Egl. y11 maps to the right arm of chromosome I 
and has a strong maternal-effect component: y11/+ daughters of y11/y11 
mothers are 75% non-Egl while y11/y11 daughters of y11/+ animals are 
uniformly Egl. y12 maps to the left of unc-32 on chromosome III and is 
a recessive suppressor of the n695 tail phenotype but a maternal 
effect suppressor of the egg-laying defect (y12/y12 daughters of y12/+ 
mothers are 77% Egl, y12/y12 daughters of y12/+ mothers are only 6% 
Egl). (It is not allelic with sup-26(n1091), a suppressor of n695 
identified by C. Trent).
y11 and y12 affect XO animals. Although XO animals of n695; sup 
strains appear to be wildtype, in a her-l+ background a small fraction 
of y12 XO animals appear intersexual. (In her-l+ strains y11 XX, y12 
XX, and y11 XO animals have no apparent phenotype.) This suggests that 
y12 affects XO animals, but that in the her-l+ background, sufficient 
her-l activity is present to effectively mask this. Therefore we 
constructed sup; her-l(e1561) strains to explore the effects of y11 
and y12 in XO animals. e1561 is a ts allele of her-l; XO animals are 
>95% male at 15  and 18 , and hermaphrodite at 20 . y11; e1561 and y12;
e1561 XO animals are exclusively hermaphrodite at all three 
temperatures. Thus, y11 and y12 can result in feminization of both XX 
and XO animals where her-1 activity is present.
We were interested in placing y11 and y12 in the context of the 
major sex determination pathway. We felt that the interactions between 
the sups and mutations in the known genes immediately upstream (sdc-1) 
and downstream (tra-2) of her-l would be especially informative. tra-2(
n1106) XX animals are weakly transformed towards a male sexual fate. 
The resulting sup; n1106 animals are indistinguishable from n1106 
alone. We are at present placing the sups in combination with the 
strong alleles n196 and e1095 of tra-2, and constructing the triple 
mutant strains sup; n1106; n695. sdc-1(n485)/Df results in XX animals 
being transformed into pseudomales (Villeneuve and Meyer, Cell, in 
press). y12; n485/Df animals are suppressed for this transformation. 
One possibility is that y12, and probably y11, modulate the major sex 
determination pathway at some point between the genes sdc-1 and tra-2.