The Role of Lysine Deacetylases in Regulating Transcriptional Dynamics at Glucocorticoid-activated Genes

点击翻译按钮获取中文摘要

Cells adapt to changes in their environment through chemical communication networks (signaling pathways) that cause changes in gene expression. Enzymes that chemically modify other proteins are key components of signaling pathways. Lysine acetylation is a protein modification conserved from bacteria to humans. Studies have revealed its widespread occurrence on cellular proteins but its roles in signaling-modulated gene expression are poorly understood. The enzymes that regulate acetylation, lysine acetyltransferases (KATs) and lysine deacetylases (KDACs), are considered to promote and impair gene expression, respectively. However, recent studies have shown that KDACs are concentrated at active genes and can promote their expression, but the underlying mechanisms are unknown. Genes are expressed in bursts of transcriptional activity interspersed with periods of inactivity. Signaling pathways change gene expression by modulating the frequency and/or the size of active bursts. Understanding how KDACs affect bursting patterns of genes will allow insight into the mechanisms underlying their ability to promote gene expression. This is important because chemicals that inhibit KDACs are present in the environment as natural products of unicellular organisms, pollutants, and drugs. Increased knowledge of the function of KDACs in gene expression is essential to assessing the impact of their inhibitors on living organisms. The work will be performed by several undergraduates and a postdoctoral fellow. The incorporation of undergraduates into the research team will provide mentoring experience to the postdoctoral fellow and serve under-represented groups through several University of Arizona programs that provide research opportunities to undergraduates from these groups. Research team members will be trained in critical thinking, problem-solving, and communication skills that will enable them to pursue careers that contribute to strengthening and diversifying the national scientific workforce. The research findings will be disseminated through publication in peer-reviewed journals and presentations at local and national conferencesThe goal of this project is to determine how KDACs regulate transcriptional bursting patterns of genes that are activated by glucocorticoids, a type of steroid hormone. The first aim will use single molecule fluorescent in situ hybridization and live cell imaging of transcription to assay the effects of KDAC inhibitors on bursting kinetics. The second aim is focused on determining where KDACs contribute to transcription in the regions in and around genes using global run-on sequencing. The study results will contribute to building improved models of signaling-induced transcriptional regulation that incorporate transcriptional dynamics and the positive contributions of KDACs to the transcriptional cycle.