Understanding mechanisms of transcriptional regulation by chromatin adaptor proteins

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PROJECT SUMMARY Precise regulation of chromatin states is critical to many vital cellular processes, including differentiation and proliferation. Chromatin misregulation has been associated with human diseases, such as cancer, intellectual disabilities, and autoimmunity, among others. Understanding the mechanisms by which genomic access is controlled at the level of chromatin is critical for revealing how cellular phenotypes are established and maintained, and how these processes are altered in disease. This study focuses on elucidating the molecular mechanisms by which the chromatin adaptor Menin coordinates protein complexes to transduce chromatin signals into transcriptional outputs. This work will test the central hypothesis that context-specific functions of Menin are dictated by its ability to bind distinct chromatin environments and recruit a variety of chromatin factors in a highly regulated manner. During the mentored phase of the award, it will determine how Menin targets specific genomic loci by integrating DNA-barcoded nucleosome libraries, epigenomics, and functional genomics approaches. This multi-tiered approach will identify combinatorial histone modifications and transcription factors, as well as delineate their biological relationships with Menin and how they contribute to its genomic localization (Aim 1). It will also identify and comprehensively characterize chromatin proteins and complexes that mediate regulatory functions of Menin at distinct cis-regulatory elements (Aim 2). During the independent phase of the award, it will determine how recurrent MEN1 mutations affect Menin’s ability to target and shape the chromatin landscape, as well as affect transcription (Aim 3). Furthermore, it will characterize the cellular and organismal phenotypes elicited by endogenous expression of MEN1 mutant alleles. Successful completion of the proposed studies will produce insights into how Menin regulates chromatin biology and transcription, and will provide a greater understanding of the mechanisms by which disease-associated mutant Menin proteins promote disease. Such knowledge could yield novel insights into the roles of chromatin and epigenetic regulators in normal physiology and pathophysiology. The integrative approaches proposed here will serve as a valuable resource for the wider scientific community interested in pursuing future studies of chromatin factors with presumed adaptor/scaffolding functions that have not been studied previously due to limitations of current methods. They will also serve as a platform for the PI to obtain new training in chromatin and chemical biology, biochemistry of transcription, structural biology, and computational epigenomics. Such training will be critical for the development of the PI’s career and will position her to effectively integrate these approaches for making novel and innovative contributions to the field of chromatin biology.