Genome-wide organization of chromatin and the transcription machinery

Published on February 4, 2014   48 min
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Hello. Today's talk is on the Genome-wide Organization of Chromatin and the Transcriptional Machinery. My name is Dr. Frank Pugh. I'm from the Center for Eukaryotic Gene Regulation at Penn State University in State College, Pennsylvania. As a way of background, I've got my undergraduate degree at Cornell University in Ithaca, New York in 1983 and then went on to graduate school in biochemistry at the University of Wisconsin at Madison, working on genetic recombination. I got my Ph.D. in 1987. I then went on to the University of California at Berkeley where I studied under Dr. Robert Teigen for a postdoc After which in 1991, I started my own lab at Penn State University and have been there ever since. And the focus of my research has been on biochemical and genomic mechanisms of eukaryotic gene regulation.
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Shown here is an image of a typical eukaryotic gene and the proteins that bind to it. The green balls that you see are the nucleosomes which package the chromatin. And you can see by that small black arrow, the TSS, is where the transcriptional start site resides. Between the minus 1 and the plus 1 nucleosomes is an open region where there are no nucleosomes. And that is where the transcription machinery assembles. And there is, perhaps, four stages that you can think of assembly. One is orchestration. That's those red circles that bind to specific DNA sequences at or near the minus 1 nucleosome. The second step involves, perhaps, chromatin remodeling, the rearrangement of proteins on the DNA surface to make the DNA more accessible to other transcription factor binding. So that's step two, access. The third step is the assembly of the general transcriptional machinery in the initiation phase. That's shown in light blue at the promoter nucleosome-free region. And then, that's followed in step four by the recruitment of RNA polymerase in elongation factors that ultimately need to enter into the gene and transcribe the genome. We're going to first talk about the organization of nucleosomes shown here.
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Genome-wide organization of chromatin and the transcription machinery

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