Fig. 1. CAM-1 structure, vulval development and vulval phenotypes, and a model for CAM-1 interaction with Wnts in C. elegans. (A) CAM-1 protein structure depicting Ig (Immunoglobulin) domain, CRD (cysteine-rich domain), Kr (kringle domain), TM (transmembrane) domain, kinase domain and S/T (serine/threonine-rich) domain. Amino terminus is to the left. Molecular lesions of cam-1 mutant alleles are given below. (B) Schematic of vulval induction process. (C-E) Nomarski images of hermaphrodite vulvae. Anterior, left; posterior, right; dorsal, up; ventral, down. (C) Wild-type vulva formed from 22 progeny of 3 VPCs: P5.p, P6.p and P7.p. (D) A UI bar-1(ga80) mutant with no VPCs induced. Arrowheads point to nuclei of P5.p, P6.p and P7.p that have adopted the F fate. (E) lin-17(n671); cam-1(gm122) double mutant displaying an OI phenotype. Arrow points to ectopic invagination caused by induction of P4.p. (F) Proposed model of CAM-1 interaction with Wnts. Arrows represent positive interaction, bars negative interaction, and dashed lines a possible interaction.