CELE_K08D9.3, K08D9.3

apx-1 encodes one of ten C. elegans DSL (Delta, Serrate, LAG-2) proteins, integral transmembrane and secreted proteins that function as signaling ligands for the Notch family receptors GLP-1 and LIN-12; in the 4-cell embryo, maternally supplied APX-1 functions as a GLP-1 ligand for an inductive interaction that specifies the fate of the ABp blastomere; later in embryogenesis, APX-1 is required for formation of the LIN-12-dependent, invariant asymmetrical twist that occurs as part of normal gut morphogenesis; during larval development, APX-1 is required redundantly with DSL-1 and LAG-2 for the LIN-12-mediated lateral signal that spatially patterns the primary and secondary vulval cell lineages; in the early embryo, APX-1 is first detected at the anterior edge of the P1 blastomere, with later expression visible in P2 at sites of contact with ABp, and in the cytoplasm of the EMS and P3 blastomeres; expression in the vulval precursor cells (VPCs) is detected in the primary VPC, P6.p, and its descendants; embryonic APX-1 expression is dependent upon PIE-1 activity, while later vulval expression is mediated by the Ras signaling pathway and the SUR-2 transcriptional cofactor.

43815

6239