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Linker histones incorporation maintains chromatin fiber plasticity.

ABSTRACT: Genomic DNA in eukaryotic cells is organized in supercoiled chromatin fibers, which undergo dynamic changes during such DNA metabolic processes as transcription or replication. Indeed, DNA-translocating enzymes like polymerases produce physical constraints in vivo. We used single-molecule micromanipulation by magnetic tweezers to study the response of chromatin to mechanical constraints in the same range as those encountered in vivo. We had previously shown that under positive torsional constraints, nucleosomes can undergo a reversible chiral transition toward a state of positive topology. We demonstrate here that chromatin fibers comprising linker histones present a torsional plasticity similar to that of naked nucleosome arrays. Chromatosomes can undergo a reversible chiral transition toward a state of positive torsion (reverse chromatosome) without loss of linker histones.

SUBMITTER: Recouvreux P

PROVIDER: S-EPMC3117191 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

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Linker histones incorporation maintains chromatin fiber plasticity.

Recouvreux Pierre P Lavelle Christophe C Barbi Maria M Conde E Silva Natalia N Le Cam Eric E Victor Jean-Marc JM Viovy Jean-Louis JL

Biophysical journal 20110601 11

Genomic DNA in eukaryotic cells is organized in supercoiled chromatin fibers, which undergo dynamic changes during such DNA metabolic processes as transcription or replication. Indeed, DNA-translocating enzymes like polymerases produce physical constraints in vivo. We used single-molecule micromanipulation by magnetic tweezers to study the response of chromatin to mechanical constraints in the same range as those encountered in vivo. We had previously shown that under positive torsional constrai ...[more]

PMID: 21641318

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