The C-elegans gene lin-36 acts cell autonomously in the lin-35 Rb pathway

The Caenorhabditis elegans gene lin-36 acts to antagonize Ras-mediated vulv al induction in a pathway that includes genes with products similar to the mammalian retinoblastoma (Rb) protein and the Rb-binding protein p48. We re port that lin-36 encodes a novel protein of 962 amino acids. We demonstrate that lin-36 functions in and is expressed in the vulval precursor cells, e stablishing that the lin-36 pathway is involved in intercellular signaling. We also report that the lin-36 pathway and/or another pathway that is func tionally redundant with the lin-36 pathway antagonize a ligand-independent activity of the receptor tyrosine kinase/Ras vulval induction pathway.