Regulated protein degradation by the unbiquitin medicated pathway is emerges as an important mechanism for regulating gene function. Although implicated in few pathways of developmental control, little is known about the extent of the role of regulated protein degradation during embryogenesis. Since broadly speaking, mis-regulation of specific genes involved in development has been implicated in several malignancies, it is likely that protein degradation will have increasing clinical significance. To explore the function of regulate protein degradation during development, we employed a novel method of screening small pools of Xenopus cDNAs to identify genes that are degraded at different stages of embryonic development. In my initial search, I found that Xom., a Xenopus homeobox gene, is degraded in a stage specific manner, most likely through the unbiquitin pathway. Previous studies suggested that Xom. plays am important role in dorsal-ventral pattern formation. Therefore, we hypothesized that the stage specific degradation of Xom. could be important for proper expression of Xom. during embryogenesis. In the future experiments, we will try to identify the mechanism of Xom degradation and study any developmental defects caused by expression of non-degradable mutants of Xor. during embryogenesis. We will also continue to screen genes that are degraded in stage specific manner and determine whether they play important role during development.