Cortical radial glia are neural stem cells that self renew and produce all cortical neuron cell types in an orderly sequential fashion. There is a fundamental gap in understanding the molecular mechanism that underlies the orderly production of neuronal cell types. Our overall goal is to understand the intrinsic timing mechanism that regulates cell fate transitions during cortical neurogenesis. We have identified the transcriptional regulator Prdm16 (Positive Regulatory Domain-containing 16) as being a critical component for regulating precisely timed cell fate transitions during cortical neurogenesis. Our studies of Prdm16 serve as an entry point to understanding the relevant genetic and epigenetic programs regulating the mode of radial glia cell division, and its relationship to neuronal fate potential. In this proposal we plan to utilize MARIS (Method for Analyzing RNA following Intracellular Sorting) to define the molecular programs regulated by Prdm16 in a cell type and stage specific manner. We will also determine the temporal pattern of PRDM16 binding and regulation of cis- regulatory elements during cortical neurogenesis. The finding from our studies will have a direct impact on increasing our understanding of how expression of early transcriptional programs and chromatin modifications can contribute to neurodevelopmental disorders.