Histone dynamics, heritability and variants

Published on October 1, 2007 Updated on February 4, 2014   38 min

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In this talk, I'd like to discuss with you the issue concerning histone dynamics, their heritability, and their existence in the form of variants.
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DNA in the nucleus is present in the form of chromatin, and that consists of a complex together with proteins. The main proteins found in chromatin are called histones. They are small, basic proteins called H3, H4, H2A, and H2B for the core histones and H1 for the linker histone. They ensure the compaction of DNA in the nucleus. In the human cells about 2 meters of DNA will fit in a volume of about a few micrometers for the diameter of common somatic cells. And this is represented here with a tennis ball on the right-hand panel. So that will impose a problem of accessibility to the DNA for all DNA transactions, which thus necessitates dynamic properties in order for all the metabolic pathways of the DNA level to operate. The additional aspect that histones can bring in the chromatin organization is a source of information. Indeed, this organization can contribute to a differential use of genetic information provided by the DNA and thus, ensure a functional diversity in the different cells. Then the question that ensues is, how is it established, and how can it be inherited? If we now come to compaction,