The CANs use the extracellular Wnt-binding domain of Ror/CAM-1 to direct epidermal patterning.

<p>(A and B) Distributions of positions of CAN cell bodies and furthest posterior CAN axon termini in <i>ror/cam-1</i> mutants and in <i>cam-1</i> mutants expressing wild-type or intracellular-domain-deleted CAM-1(ΔIntra) only in the CANs. In non-<i>ror/cam-1</i> rescue experiments, CANs were visualized with the <i>kyIs4[Pceh-23::gfp]</i> transgene. In <i>ror/cam-1</i> rescue experiments, CANs were visualized by expression of GFP-tagged Ror/CAM-1 in the CANs. In <i>ror/cam-1</i> rescue experiments, strains also harbored an <i>egf</i>/<i>lin-3(lf)</i> mutation. <i>x</i>-Axis indicates Pn.p or Pn.px positions. H, head/pharyngeal region. <i>p-</i>Values were calculated using a two-tailed Mann-Whitney <i>U</i> test. (C) Ror/CAM-1 inhibits vulval fate signaling in central vulval progenitors. (D) Transgenic CAN-specific expression of Ror/CAM-1::GFP restores inhibition of vulval development in <i>ror/cam-1</i> mutants. (E) Transgenic CAN-specific expression of a Ror/CAM-1::GFP mutant lacking the intracellular domain (ΔIntra, see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001465#pbio-1001465-g006" target="_blank">Figure 6C</a>) also restores inhibition of vulval development in <i>ror/cam-1</i> mutants. In (D) and (E), scale bar is 20 µm. (F) Under physiologic conditions, the majority of Ror/CAM-1 inhibition of vulval fate signaling is mediated by the CANs. If the CAN cell bodies are anteriorly displaced and the posterior axons are severely foreshortened, loss of Ror/CAM-1 activity from all cells does not further increase P3.p progenitor frequency or the amount of vulval development in sensitized backgrounds. Drawings depict the cellular distribution of Ror/CAM-1 as described in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001465#pbio-1001465-g006" target="_blank">Figure 6E</a>. M, muscle cells; N, neurons; P, vulval progenitors. In (C–E), vulval fates: number of vulval progenitor cells adopting vulval fates. Wild-type is 3.00. <i>p-</i>Values were calculated using a two-tailed Student's <i>t</i> test. The <i>PCAN::cam-1::gfp</i> and <i>PCAN::</i>Δ<i>Intra::gfp</i> rescuing transgenic arrays are <i>dyEx44</i> and <i>dyEx45</i>, respectively.