My laboratory studies the process of signal transduction during animal development. A basic question in developmental biology is how do undifferentiated cells respond to signals from other cells in order to differentiate correctly? We are addressing this question by studying the development of the vulva of the nematode worm, Caenorhabditis elegans. During development, six cells in the worm choose one of four different cell fates based on external signals they recieve. Three of the cells divide and form the vulva, while the other three become part of the skin. These cells respond to the signals by using a Ras signaling pathway, a cascade of proteins that has been conserved across species from C. elegans to mammals. Mutations in some components of this pathway cause tumors in humans. We have isolated mutations in several new genes which perturb the normal pattern of vulval development in interesting ways. The main focus of my lab is cloning and understanding the genes identified by these mutations. The first of these genes, called bar-1, encodes a C. elegans b-catenin/armadillo-related protein. Proteins of this type function in a different type of evolutionarily-conserved signal transduction pathway, the Wnt pathway. We are investigating how BAR-1 protein functions during vulval induction, how BAR-1 interacts with the Ras signaling pathway, and whether BAR-1 controls the expression of C. elegans HOX genes (transcription factors that regulate cell fate).