Specification of Ectoderm: Epidermal versus Neural Fate

Ken W.Y. Cho

University of California, Irvine

BMP signaling plays a major role in determining whether ectodermal cells adopt an epidermal or a neural fate in both vertebrates and invertebrates.  In the presence of BMP signaling cells differentiate into an epidermal lineage, whereas in the absence of BMP signaling cells will differentiate into neural cells.  To better understand the process of BMP mediated cell fate specification, we identified immediate early genes regulated by BMPs using DNA microarrays and used a phylogenetic footprinting method to identify a conserved transcriptional regulatory mechanism.  We also identified a set of genes that are induced immediately after inhibition of BMP signaling and a similar approach is currently being used to identify an enhancer that responds to neural induction to uncover a transcriptional regulatory mechanism regulating neural induction.  During the course of a large-scale gene profiling, we also find that an aspect of neural regulatory mechanism is quite similar to that of pancreas development, and started investigating the roles of transcription factors that are expressed in both the nervous system and pancreas.  Interestingly, some of these factors can covert hepatic cells into a pancreatic lineage and this approach may open the door to eventual use of similar techniques in β-cell replacement therapy for treatment of type I diabetes.