Both reporters are expressed at the time of vulval induction at equal levels in P5.p, P6.p, and P7.p. After the first round of cell divisions, the translational DEP-1::GFP reporter is down-regulated in the primary lineage, but expression persists in the secondary vulval cells until the L4 stage. DEP-1::GFP expression is lower in P6.p than in P5.p or P7.p descendants in 82% of L3 and in 95% of L4 larvae (n = 26 and n = 21, respectively). A similar reduction of the expression in the primary lineage is observed with the transcriptional reporter, although the down-regulation in the primary lineage only becomes apparent at the Pn.pxx stage.
dep-1p::gfp expression is lower in P6.p than in P5.p or P7.p descendants in 80% of the L3 larvae (n = 78). In most cases (e.g., 17 out of 18 larvae at the Pn.px and Pn.pxx stages), DEP-1::GFP expression is low or absent in cells expressing high LET-23 EGFR levels and vice versa.