? ? Programmed cell death or apoptosis plays an essential role in tissue homeostasis and proper development of an organism. The aberrant regulation of cell death may lead to the development of human diseases including cancer, neurodegenerative and autoimmune diseases. Thus, the regulation of cell death must be tightly controlled. In C. elegans, endogenous CED-4 localizes to the mitochondria in a complex with the CED-9 protein, which antagonizes the pro-death activity of CED-3 and CED-4, in non-apoptotic embryos. However, in embryos induced to die, CED-4 translocates to the nuclear envelope. Although the relocalization of CED-4 to the nuclear envelope coincides with programmed cell death it is unclear whether this process is required for the activation of CED-3 or the execution of apoptosis. In this proposal, I will initiate studies to determine the mechanism of CED-4 transport to the nuclear envelope during apoptosis. Using a screen for mislocalized CED-4::GFP we have isolated four mic mutants. I will characterize through genetic, molecular, and biochemical analysis these mutants, first examining their affect on nuclear apoptotic events. Then mic-1(sm] 58) and mic-2 (sm160) will be cloned by cosmid rescue. Finally, I propose to determine whether the mic genes act in a complex with CED-4 and if during apoptosis other proteins that translocate to the nucleus are affected by the mic genes. Through these studies I hope to understand the mechanism underlying CED-4 translocation to the nucleus and determine the role of this event in programmed cell death. ? ? ?
