| During Caenorhabditis elegans vulval induction, cell signaling causes initially equipotent cells to express a reproducible pattern of cell fates. The position of the inductive anchor cell determines the pattern of vulval precursor cell fates: the precursor cell (P6.p) closest to the anchor cell expresses the 1;We cloned lin-7 and found it encodes a cell junction-associated protein with a PDZ/DHR domain. A LIN-7-GFP fusion protein colocalized with cellular junctions in the intestine and overexpressed LIN-7 colocalized with the cellular junctions in the Pn.p cells. lin-7 gene activity is required in the Pn.p cells for normal vulval development. LIN-7 is involved in localizing the LET-23 receptor tyrosine kinase, since a LET-23-GFP fusion protein is associated with the cell junctions of vulval precursor cells in wild-type animals, but is mislocalized to the apical membrane domain of these cells in lin-7 mutants. lin-2, which has a vulvaless mutant phenotype and encodes a membrane-associated guanylate kinase (MAGUK), is also required for LET-23 receptor localization. These results indicate that the polarized distribution of signalling components plays an important role in cell signaling in vulval epithelial cells. |
