Description:

The Department of Biochemistry & Molecular Genetics presents:

Carl Wu, PhD
Bloomberg Distinguished Professor
Department of Biology, Johns Hopkins University
Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine

Presentation: 

"The biogenesis and regulatory dynamics of chromatin accessibility for gene expression"

Abstract:

The creation of DNA accessibility in chromatin constitutes the first stage of eukaryotic transcriptional control.  The establishment and maintenance of DNase hypersensitive, Nucleosome Depleted Regions (NDRs) at regulatory DNA elements require collaboration between ATP-dependent chromatin remodeling complexes that mobilize nucleosomes, and certain transcription factors (TFs) that are unimpeded by nucleosome architecture. We use gene editing and single-molecule fluorescence microscopy to directly observe and quantify factor kinetics in real time, in vitro and in living cells. The results show that such TFs bind to chromatin transiently and with distinctive residence times on a ~100 sec timescale, enabling nucleosome displacement and highly dynamic assembly of the transcription preinitiation complex on a timescale of seconds. Our findings suggest that regulation of gene expression involves kinetic competition between multiple players for limited DNA space at gene promoters and enhancers.

Host: Dr. Daniel Foltz, Professor, Biochemistry and Molecular Genetics