LIN- 32::GFP is first visible in wild-type worms in the ray neuroblasts (Rn.a cells) of L3 males and persists in the ray lineage. In
mab-3 mutants, fewer cells of the ray lineage express LIN-32::GFP. The number and position of these LIN- 32::GFP-expressing cells is consistent with the forma- tion of T rays, but very few mature V rays. By contrast,
mab-3 ref-1 double mutants display a pattern of LIN- 32::GFP expression indistinguishable from that of wild- type. This strongly suggests that REF-1 negatively regulates
lin-32 expression in
mab-3 mutant males.