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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.
