Dynamique à l'équilibre et hors d'équilibre de la chromatine visualisée par microscopie de force atomique : effet des variants d'histones et des facteurs de remodelage

Abstract : The organization of DNA into nucleosome interferes with several cellular processes. To overcome this physical barrier, the cell recruits ATP-remodeling machines and histone variants. In this work, we use Atomic Force Microscopy to visualize isolated mono- and oligo-nucleosomes at equilibrium and out of equilibrium.
We show that H2A.Bbd variant incorporation into the nucleosome modifies both the structure and dynamics of the mono-nucleosome and that its presence alters the ability of chromatin to form a higher order structure. Using a polymer model, we quantitatively explain this behavior by the mono-nucleosome flexibility.
Then, studying the mechanism of nucleosome remodeling by SWI/SNF and RSC on mono-nucleosomes, we reveal a reaction intermediate visible as an over-complexed nucleosome before the appearance of the final slided state. Focusing on di-nucleosomes we report various slided states and construct a stochastic model showing that RSC is a processive and sequential randomizer.
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https://tel.archives-ouvertes.fr/tel-00358612
Contributor : Cendrine Moskalenko <>
Submitted on : Tuesday, February 3, 2009 - 10:20:33 PM
Last modification on : Thursday, April 19, 2018 - 2:54:03 PM
Long-term archiving on : Tuesday, June 8, 2010 - 9:52:50 PM

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  • HAL Id : tel-00358612, version 1

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Fabien Montel. Dynamique à l'équilibre et hors d'équilibre de la chromatine visualisée par microscopie de force atomique : effet des variants d'histones et des facteurs de remodelage. Physique [physics]. Ecole normale supérieure de lyon - ENS LYON, 2008. Français. ⟨tel-00358612⟩

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