Download or read book Epigenetic Basis for the Regulation of Estrogen Receptor Alpha Activity in Breast Cancer Cells written by and published by . This book was released on 2009 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: A key factor involved in breast cancer development and progression is the estrogen receptor alpha (ER). Genome-wide computational studies on ER have identified over 70,000 putative Estrogen Response Elements (EREs) in the human genome. However, a genome-wide functional study using ChIP-Chip, has indicated that less than 1/10 of all putative ER binding sites are recognized by the receptor following estrogen stimulation in breast cancer cells. Through genome-wide positional analyses, we demonstrate that ER recruitment is dependent on a specific epigenetic signature characterized by mono and dimethylation of lysine 4 on histone 3 (H3K4me1/me2). Furthermore the pioneer factor FoxA1 translates this epigenetic signature into changes in chromatin structure in a cell type-specific manner for transcription factors, such as ER. Hence, this allows for the establishment of lineage-specific transcriptional enhancers and programs.