Chromatin Regulation of the EGFR Locus in Human Mammary Epithelial Cells

摘要

Cell-Extracellularmatrix (ECM) adhesions structurally alter the cells aswell as provide signals critical for the cell differentiation and tissue-specific gene transcription. We show showed that the ECM induce global deacetylation of his tones H3 and H4 in human breast epithelial cells and that this deacetylation correlated with a global reduction in gene expression. To determine how chromatin structure regulates differentiated gene expression in 3D culture we used mammary-specific case in genes as models. We identified that transcription factors Stat5 and CIEBP beta were regulated by ECM. Chromatinimmunoprecip itation(ChlP)assays demonstrated that levels of acetylated histones as well as binding of Stat5 and CIEBP betain the case inpromoters increased in response to ECM and prolactin treatment. However trichostatin A(TSA)-induced histoneacetylation failed to activate-case in expression suggesting that histoneacetylationis not sufficient for the gene transcription. Introduction of adominantnegative Brg 1 significantly reduced both beta-andgamma-casein expression indicating that ATP-depend entchromatinremodeling is required for transcription of these two milk proteingenes. Thus ECM-and prolactin-regulated transcription of the mammary- specific case in genes requires the concertedaction of histoneacetylation ATP- depend entchromatinre modeling and activation oftranscription factors.