12:00 AM - 10:30 AM on Friday, February 22, 2013
Location: Virginia Tech Research Center -Arlington, Room 4-024
Invited Speaker: Dr. Golnaz Vahedi, NIH (1st author of a recent paper in Cell).
Although we often focus on the selective expression of genes when we consider cell identity, very little of the genome consists of genes. Rather, most of the genome consists of instructions or regulatory elements that turn genes on and off. So, in consideration of control of cell identity it seems logical to consider how extra-genic portions of the genome might contribute. One important group of these regulatory elements is transcriptional enhancers. Enhancers are DNA sequences that recruit transcription factors to promoters and “enhance” transcription of these target genes, regardless of their location or orientation. In this talk, I will introduce how the epigenetic status of a cell can be used to globally map active enhancers. I will use T cells as a model of differentiation, mapping the activity of cell-type-specific enhancer elements in two distinct T cell populations. Mapping the chromatin signature of active enhancers, I will demonstrate that signal transducers and activators of transcription (STAT) proteins have a major impact on the activation of lineage-specific enhancers. Transcriptome analysis further supports a functional role for enhancers regulated by STATs. Importantly, expression of lineage-defining master transcription factors in STAT-deficient cells fails to fully establish the chromatin signature of STAT-dependent enhancers. Thus, these findings point to a critical role of STATs as environmental sensors in dynamically shaping the specialized enhancer architecture of differentiating cells.