Project Summary Understanding the molecular mechanisms of how cells respond to changing environmental cues and integrate various signals, especially in the context of an intricate tissue or organism, is a major challenge. In the mammalian intestine, inputs from diet and the commensal microbiota can occur in the form of metabolites that act on neighboring intestinal epithelial cells and impact physiology. One such class of metabolites are short chain fatty acids (SCFAs), which are generated by microbes through the breakdown of dietary fiber. Recently, SCFAs have been detected as chemical modifications on histone proteins, called histone acylations. While certain histone acylations have been reported to positively regulate transcription, including the well-studied histone acetylation, the mechanistic functional role of other acyl marks and especially their physiological roles, are largely unknown. In addition, alterations in the chromatin landscape can have consequences on the regulation of gene expression and downstream cellular functions. Thus, my overall goal is to gain mechanistic understanding of how histone acylations are regulated and govern cell function in vivo. My central hypothesis is that different histone acylations have distinct functions in gene regulation through playing different roles in particular tissues and gene sets, and that exogenous cues regulate the balance of histone acylations that can drive cellular phenotypes. I will use the murine intestinal tract as a model system, which will likely elucidate physiological functions and delineate regulatory mechanisms of histone acyl marks through the following Aims: (1) I will study how acyl reader complexes regulate gene expression under particular cell contexts, (2) I will determine how histone acylations regulate intestinal epithelial cell fate, and (3) I will investigate the regulation of histone acylations through cellular metabolism. This proposed work will importantly build off of my postdoctoral studies and will provide me with critical training towards becoming an independent investigator. During the mentored phase of this award, I will gain essential training in animal work, chromatin biology, and metabolism. This support, along with the outstanding environment at Rockefeller University and mentorship from Dr. Allis, will set me up for success for the independent portion of this award. Importantly, I will continue to foster collaborations and receive additional mentoring from my Advisory Committee, who will provide crucial expertise in the intestine, microbiota, and metabolism, and facilitate my transition to independence. Together, this training and support will promote my scientific career and completion of this research proposal will advance our understanding of the physiological roles of novel histone acyl marks.