Function of Chromatin Features in Cellular Programming

PROJECT SUMMARY / ABSTRACT Maintaining stable gene transcription patterns is critical for cellular programming. Likewise, orderly switching from one transcription pattern to another, termed reprogramming, is necessary for development, as well as for numerous other biological processes. Dysregulated reprogramming can have catastrophic consequences, with outcomes ranging from developmental disease to cancer. Notably, epigenetic abnormalities, failure to differentiate, and inappropriate cellular programming are intricately linked to carcinogenesis. Our objective is to define the function of H2A.Z (a variant form of histone H2A) in regulating cellular programming. We will utilize cultured mouse cells, human cancer cells, and developing zebrafish embryos, combined with a series of next- generation genome-wide sequencing approaches, to functionally test how H2A.Z patterns regulate several aspects of cellular reprogramming, including transcriptional activation. Our prior studies have uncovered considerable diversity in H2A.Z function, including regulation of chromatin accessibility, transcription factor binding patterns, bivalent chromatin establishment, and nucleosome remodeler function. One interesting possibility is that H2A.Z interacting proteins influence its genomic localization and mediate its function. To test this hypothesis, we will genetically manipulate the regulators of H2A.Z localization in zebrafish embryos, and cultured mouse cells, and then assess outcomes via genomics and proteomics studies. Successful completion of this project will define the role of H2A.Z in controlling gene expression patterns and in cellular programming. We propose that this broader concept, where changes in epigenetic marks underlie cellular reprogramming, might be a general principle in biology, with relevance to developmental biology, stem cell function, and carcinogenesis.