Regulation of expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, that when mutated causes Cystic Fibrosis (CF).
Our work over many years has been pivotal in elucidating of the tissue-specific and temporal regulatory mechanisms for CFTR. The CFTR gene encompasses nearly 200 kb of genomic DNA which is isolated within a single topologically associating domain (TAD). Within this, distal cis-acting, tissue-specific regulatory elements are brought into close proximity with the gene promoter to modulate its activity. We identified many of the cell-type-selective transcription factors (TFs) that bind to these cis-elements. In recent work we revealed the targets for several of the key TFs genome wide, using ChIP-seq together with open chromatin mapping by DNase-seq. These studies enabled us to start determining the transcriptional networks that control epithelial cell identity and differentiation, and how individual TFs contribute to this coordinated gene expression.
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Current Projects:
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CRISPR/Cas9 protocols to manipulate enhancers in the CFTR locus and determine their interdependency.
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Investigation of TFs that repress CFTR gene expression.
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Identification of regulatory element variants in CF patients with undefined mutations.
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Determine developmental regulatory elements of CFTR in hiPSCs.
Recent Publications:
Yang, R., Kerschner, J.L., Gosalia, N., Gorsic, L.K., Neems, D., Safi, A., Kosak, S.T., Crawford, G.E., Leir, S-H., Harris, A. (2016) Differential contribution of cis-regulatory elements to higher order chromatin structure and expression of the CFTR locus. Nucl. Acids. Res. 44:3082-94 Epub Dec 15 2015. PMCID: PMC4838340
Gillen, A.E., Yang, R., Cotton, C.U., Perez, A., Randell, S.H., Leir, S-H., Harris, A. (2018) Molecular characterization of gene regulatory networks in primary human tracheal and bronchial epithelial cells. Journal of Cystic Fibrosis. In Press. Epub Feb 17th.
Mutolo, M.J., Leir, S-H., Fossum S.L., Browne, J.A., Harris, A. (2018) A transcription factor network represses CFTR gene expression in airway epithelial cells. Biochemical Journal, In Press.