The receptor tyrosine kinase/Ras signal transduction pathway is conserved from humans to Caenorhabditis elegans. Although this pathway has been elucidated from the ligand to the transcription factors in both humans and worms, little is known about the targets and downstream factors responsible for the execution of the Ras pathway. Within C.elegans, the Ras pathway induces the development and morphogenesis of the vulva. Factors nessesary for execution of the Ras pathway will be isolated through a lin-1 suppressor screen. lin-1 is the furthest known downstream effector in the C. elegans Ras pathway. The gene abi-2, which controls one of the first morphogeneic changes in vulval development, will also be analyzed for its regulation by the Ras pathway. Combinations of these experiments will allow me to study the molecular mechanisms that execute vulval morphogenesis following an inductive event and may identify candidate factors responsible for the execution of Ras signaling and for tissue differentiation.