Research in my lab explores how specific signal transduction pathways regulate lymphocyte differentiation. Lymphocytes develop from hematopoietic stem cells and go through characteristic stages of differentiation that result in the formation of functional B or T cells. These stages are carefully regulated by the action of growth factor and cytokine receptors, as well as the clonotypic B cell and T cell antigen receptors. A key question is how distinct signaling pathways downstream of these receptors regulate various aspects of B and T cell maturation. Current efforts in the lab seek to elucidate how two such pathways, the Ras and Jak/STAT signaling cascades, entrain these developmental processes. This is being done using a variety of techniques, including the use of mice expressing dominant negative and activated Ras, Raf and STAT transgenes, in concert with subtractive cDNA libraries and gene microarray technology. In addition, we have developed a novel, chemical-induced dimerization approach that allows us to selectively activate specific signaling pathways, and identify their targets, in the absence of confounding signals from other signal transduction pathways. Using these approaches, we seek to identify novel Ras and Jak/STAT targets, in both developing B and T cells, that regulate lymphocyte proliferation or differentiation.