Dissecting the Role of Nucleosomes in Transcription and the Application of CRISPR/Cas9 Technology

In the 43 years since the first observation of nucleosome core particles as beads on a string, our understanding of the relationship between nucleosome structure and its function in living cells has made giant strides. Despite this progress, many questions remain unanswered regarding the role of nucleosomes in transcription initiation, and their interaction with the core transcriptional machinery. Here, I present my progress on addressing the role of TAF1 recognition of acetylated histone H4 tails, and its effect on transcription initiation and start site selection. Preliminary results suggest that H4 acetylation may play a role in start site selection.One remarkable advancement in technology that will undoubtedly help answer remaining questions in chromatin biology is the repurposing of the prokaryotic CRISPR-Cas system to edit eukaryotic genomes with exquisite precision. Ironically, a tool that may shed light on complex eukaryotic chromatin interactions was evolved in a prokaryotic environment. My work with in vitro nucleosomes positioned me to address whether Cas9 is capable of engaging nucleosomal DNA. Both in vitro and in vivo analyses done in collaboration with Max Horlbeck and Jonathan Weissman at UCSF suggest that nucleosomes pose a strong barrier to Cas9