In C. elegans, the descendants of the 1° vulval precursor
cell (VPC) establish a fixed spatial pattern of two different cell fates: E-F-F-E. The two inner granddaughters attach to the somatic gonadal anchor cell (AC) and generate four vulF cells, while the two outer granddaughters produce
four vulE progeny. zmp-1::GFP, a molecular marker that
distinguishes these two fates, is expressed in vulE cells, but not vulF cells. We demonstrate that a short-range AC signal is required to ensure that the pattern of vulE and vulF fates is properly established. In addition, signaling between the inner and outer 1° VPC descendants, as well as intrinsic polarity of the 1° VPC daughters, is involved in the asymmetric divisions of the 1° VPC daughters and the
proper orientation of the outcome. Finally, we provide
evidence that RAS signaling is used during this new AC
signaling event, while the Wnt receptor LIN-17 appears to
mediate signaling between the inner and outer 1° VPC
descendants
