The project attempts to answer the following question: What are the neural stem cell (NSC) transcription factors (TFs) that determine neurogenesis and those that determine astrogenesis? NSCs co-exist with other neural cell types during differentiation and communicate with other cells in the NSC niches. Furthermore, expressions of the NSC TFs are time dependent. These conditions make it very challenging to analyze TFs of NSCs. The technique I will use to address the challenge is called TU-tagging, which utilizes the UPRT enzyme from Toxoplasma gondii that is not found in mammalian cells to incorporate a thio-tag into the mRNA only in a specific cell type. A long-term aim is to apply TU-tagging to extract cell type-specific mRNAs in the in vitro model of neural differentiation. In my work, preliminary experiments have been performed and reagents have been generated to help meet this goal. Ubiquitous and cell type-specific UPRT expression vectors for TU-tagging have been made and were used to validate the method using a P19 cell line that is a traditional model of neural differentiation.