Figure 3. Sex-specific glial gene expression requires the NF-Y repressive complex acting in the glial cell downstream of MAB-3.

(A) Schematic of forward genetic screens in which animals expressing grl-18 reporters were mutagenized with ethyl methanesulfonate (EMS). Mutant males lacking grl-18 expression in CEPso glia (OFF mutants, left) and mutant hermaphrodites exhibiting inappropriate grl-18 expression in CEPso glia (ON mutants, right) were isolated, and the causal mutations were identified (see also Table 1 and STAR Methods). (B) Schematic of NFYA-1 protein showing effects of novel alleles (hmn316, hmn317, hmn319) and an existing 1837 bp deletion (ok1174). Working model of the NF-Y repressor complex (NFYA-1, NFYB-1, NFYC-1) acting with glial-specific cofactors to inhibit male-specific gene expression, subject to de-repression by MAB-3. (C) Fraction of 1-day adult wild-type or nfya-1, nfyb-1, or nfyc-1 mutant hermaphrodites that express grl-18pro:GFP in CEPso glia. nfya-1 mutant is shown alone (−) or with rescuing nfya-1 cDNA under control of nfya-1, CEPso-specific (col-56), or pan-neuronal (rab-3) promoters. See Figure S3 for quantification of other known sex differences in neurons and glia in nfya-1 mutants. (D) Epistasis analysis showing fraction of 1-day adult mab-3(mu15), nfya-1(ok1174), or mab-3(mu15); nfya-1(ok1174) mutants of each sex that express grl-18pro:GFP in CEPso glia. (E) Genetic model of grl-18 regulation in CEPso glia. Sample sizes are above the bars of each graph. Error bars, SEM.