The ephrin VAB-2/EFN-1 functions in neuronal signaling to regulate epidermal morphogenesis in C-elegans

The Eph receptor VAB-1 is required in neurons for epidermal morphogenesis d uring C. elegans embryogenesis. Two models were proposed for the nonautonom ous role of VAB-1: neuronal VAB-1 might signal directly to epidermis, or VA B-1 signaling between neurons might be required for epidermal development. We show that the ephrin VAB-2 (also known as EFN-1) is a ligand for VAB-1 a nd can function in neurons to regulate epidermal morphogenesis. In the abse nce of VAB-1 signaling, ephrin-expressing neurons are disorganized. vab-2/e fn-1 mutations synergize with vab-1 kinase alleles, suggesting that VAB-2/E FN-1 may partly function in a kinase-independent VAB-1 pathway. Our data in dicate that ephrin signaling between neurons is required nonautonomously fo r epidermal morphogenesis in C. elegans.