Fig. 5. EGL-43 is involved in AC invasion as a downstream target of HLH-2 and FOS-1. Animals containing cdh-3::CFP (red) were injected with egl-43 (PR-domain)::YFP constructs. (A-F) The PR-YFP transgene is expressed (green) in the VU and DU lineages as well as in the AC from early L2 when using the wild-type egl-43 regulatory region (A,B), and shows the AC (cdh-3::CFP, white) invasion defect (E). The transgene is expressed in the VU and DU lineages from late L2, but in the AC from mid-L3, when using the mutated E-boxes (C,D), and shows normal AC invasion (F). (G-L) egl-43 RNAi eliminates expression of zmp-1::GFP (G,H) and him-4::GFP (I,J) in the AC (arrow), but not of fos-1::YFP (K,L). egl-43 RNAi resulted in two ACs in which fos-1::YFP is expressed higher than in the neighboring gonadal cells (L, arrows). (M-R) fos-1 RNAi greatly reduces egl-43 expression in the AC, and in the DU and VU descendants at the L3 molt (M,N) and at mid-L3 (Q,R), but not at mid-L2 (O,P). Animals from a transgenic line that expresses egl-43(exon-5)::YFP were used for the fos-1 RNAi.