Chromatin Dynamics of the CFTR locus

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DESCRIPTION (provided by applicant): Since the discovery of the gene responsible for cystic fibrosis (CF) encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, several therapeutic approaches have emerged that have extended and enhanced the quality of life for patients with CF. However, such advances in clinical approaches used for treating CF still remain at odds with our current knowledge involving the epigenetic regulation and transcriptional control of the CFTR gene (CFTR). Despite the molecular and genetic characterization of mutations in patients and families afflicted with CF, the relationship of well -characterized polymorphisms still remain inconsistent in predicting disease outcome associated with CF. This reality stresses a lack in understanding how CFTR is regulated and how transcription of corresponds with the CF phenotype. The objective of this application is to determine the fundamental mechanisms in chromatin that regulate CFTR transcription. Gene regulation occurs within the native chromatin environment through the alteration of nucleosome mobility, histone content or variation, and post-translational modification of histones in chromatin. Furthermore, less is still known of the three dimensional (3D) characteristics of CFTR transcription requiring the cooperative interactions between other gene loci that give rise to the high order chromosomal organization for temporal and spatial control. Despite the advance in the characterizing many covalent post-translational histone modifications and their contribution to the epigenetic programming of gene expression, absent among this particular scientific milestone has been the functional characterization of ATP - dependent chromo - helicase domain (CHD) proteins and their contribution to specific gene expression programs. Recent genetic and biochemical examination of only a few mammalian CHD proteins reveal the remarkable importance of these gene products during development and in disease. Therefore, efforts to functionally characterize the individual members of the CHD family of proteins will likely have profound impact on human health and understanding disease patho-physiology. We propose the following specific aims. First, we will investigate the role of CHD6 to cooperate with additional transcriptional proteins such as CTCF to regulate CFTR. These studies will characterize specific nuclear protein interactions with CHD6 to regulate CFTR gene transcription. Second, we will determine the patho -physiology associated with conditional disruption of CHD6 in mice and study the consequence on the epigenetic signature and transcription of CFTR. Finally, we propose to characterize the role of CHD6 to participate as a stricture with CTCF for the convergence of multiple loci with CFTR to coordinate a 3D transcriptional program using ChIP sequencing, 3C/4C, and RNA FISH approaches to understand the modified or variant histone signatures and dynamics of chromosomal exchange associated with CHD6.