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Printable Handouts
Navigable Slide Index
- Introduction
- Chromatin structure
- Different modifications identified on histones
- Dynamic regulation of histone methylation
- The chemistry of lysine methylation on histones
- Polycomb complexes: overview
- Polycomb complexes: mechanisms
- Epigenetic gene silencing by Polycomb proteins
- Recruitment & displacement of Polycomb proteins
- PcG genes and human cancers
- Variations of Polycomb repressive complexes
- CBX family of proteins: chromodomain
- CBX family of proteins: recruitment of PRC1
- PRC1 in mES and differentiated ES
- Polycomb complexes regulate Polycomb genes
- PRC1 complex in mES contains various proteins
- Cbx7 overlaps with PRC1/PRC2 target genes
- Cbx7 function in pluripotency and transcription
- Polycomb protein levels in embryoid bodies (EB)
- New PRC1 complexes during EB differentiation
- Summary so far
- How is Polycomb binding regulated?
- Polycomb binding regulation
- The Polycomb-like gene family
- PHF19 associates with PRC2
- The Tudor domain of Phf19 binds to H3K36me3
- Genome-wide peaks of H3K27me3 & H3K36me3
- The Tudor domain with a methylated peptide
- Link between Phf19 and Polycomb
- PRC2 is required for Phf19 occupancy
- Phf19 is required for PRC2 occupancy
- Phf19 in mES cells
- Changes during formation of EB
- Phf19 in ES cell differentiation
- Phf19 regulates PRC2 activity (1)
- Phf19 regulates PRC2 activity (2)
- Acknowledgements (1)
- Acknowledgements (2)
Topics Covered
- Chromatin structure
- Histone modification and regulation of methylation
- Polycomb complexes (gene silencing, recruitement & displacement of proteins, protein levels in embryoid bodies, binding regulation)
- PcG genes and human cancers
- Variations of Polycomb Repressive Complexes and their associations with polycomb proteins
- CBX family of proteins
- The Polycomb-like gene family
Links
Series:
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Talk Citation
Di Croce, L. (2014, February 4). Role of polycomb proteins in gene transcription, stem cell and human diseases [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 8, 2024, from https://doi.org/10.69645/VQWE3616.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Luciano Di Croce has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
A selection of talks on Genetics & Epigenetics
Transcript
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0:00
Role of Polycomb Proteins in Gene Description,
Stem Cells and Human Diseases,
by Luciano Di Croce, from the Gene
Regulation, Stem cell, and Cancer Department,
ICREA, and Center for Genomic
Regulation, Barcelona, Spain.
0:17
The DNA of eukaryotic cells is
organized in chromatin fibers,
where the nucleosome forms
the basic repeating unit.
Each nucleosome comprises 147 base
pairs of DNA, which is wrapped
in 1.8 elegant turn around an
octamer of four highly evolutionarily
conserved histone protein, which are
histone H two A, histone H two B,
histone H three, and histone H four.
These four structure, which is
often called as 11 nanometer fibers.
The histone H1 lines to deliver DNA
between two addition nucleosomes,
causing further compaction
of the chromatin fibers
into higher order structure,
often refer as a solenoid or as 30
nanometer fibers.
The analyses of the crystal
structure of the nucleosome,
which was solved in 1998 by the
group of Luger and Richmond,
reveal that on terminal a part of the histone tail
are flexible and protrude
outside from the nucleosome core.
The histone tail
undergoes a large number
of post-translational modifications.
1:32
Some of these modifications
are illustrated in this slide.
For example, lysine can
be acetylated, methylated,
while arginine can
also be methylated.
Serine and threonine
can be phosphorylated.
Lysine can be also
to be ubiquitinated
or sumoylated and so forth.
Too many functions have been ascribed for histone modifications.
For example, acetylation
of lysine neutralizes
the positive charge at histone tail.
And two, altering
histone DNA interaction
reduces interaction
between different histones,
in addition to nucleosomes.
Moreover, as illustrated in
the bottom part of this slide,
several post transcriptional modifications of histones
generate docking side, or modulate
the affinity of nuclear proteins
for chromatin.
The specific recognition
of histone modification
is achieved by a dozen
protein domains, which
are present in a large number of
chromatin-associated proteins.
In turn, these adaptive proteins
are usually part of large protein
complexes, implicated in chromatin
remodeling, prescription,
or for further modifications
of histone tails.
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