Figure 5. SUP-35 overexpression phenocopies pha-1 loss of function.

(A) Representative genetic strategy applied to assay the effects of SUP-35 overexpression in wild type and in sup-36 and sup-37 mutant backgrounds. Wild-type males carrying an integrated myo-2::GFP reporter (mIs11) were crossed into pha-1; sup-36 hermaphrodites carrying a sup-35-overexpressing extrachromosomal array (fdEx59). Although this mating failed to produce viable F1 cross-progeny hermaphrodites, fertile cross-progeny males were generated, which were identified by expression of the myo-2::GFP reporter. F1 cross-progeny males were then mated to wild-type or sup-36 hermaphrodites, and cross-progeny were identified based on the myo-2::GFP reporter. Mating into the N2 strain failed to produce viable cross-progeny males or hermaphrodites, whereas mating to sup-36 generated both viable and non-viable male and hermaphrodite F2 cross-progeny. Non-viable F2 cross-progeny from both matings displayed a Pun (Pharynx unattached) phenotype, and these animals uniformly carried the fdEx59 array. Identical results were also obtained for sup-37 mutants using the above strategy, and similar findings were obtained for both sup-36 and sup-37 using additional genetic approaches (see Materials and Methods). (B,C) DIC images of a typical non-viable embryo (B) and larva (C) obtained through the above mating. Note the Pun phenotype. Black and white arrowheads indicate the anterior and posterior pharyngeal boundaries, respectively. Scale bar in C, 1 µm for B,C.