Fig. 1. PUF proteins that negatively regulate vulval development. (A) Intron-exon structure and alleles of puf-8, fbf-1 and fbf-2. White boxes indicate the 5'UTRs, white boxes with arrowheads the 3'UTRs, grey boxes the coding regions and black boxes the PUF repeats. (B-E) Nomarski images of the vulval cells in L4 larvae of (B) gap-1(ga133), (C) puf-8(zh17); gap-1(ga133), and of (D,E) fbf-1(ok91) fbf-2(q704); gap-1(ga133) animals. In all panels, anterior is to the left and ventral is to the bottom. Note the ectopic induction of P4.p and P8.p (arrows in C,D,E). Arrowhead in E indicates an example of defects in the 2° cell lineage generated by P5.p resulting in the detachment of the P5.p descendants from the cuticle in a fbf-1(ok91) fbf-2(q704); gap-1(ga133) larva. Scale bar: 10 µm.