Main topic

Modeling of the statistical and mechanical behavior of single chromatin fiber in magnetic tweezers experiments.

Keywords

Chromatin architecture, nucleosome polymorphism, single molecule, magnetic tweezers.

Reference

Nature Structural and Molecular Biology - advance online publication
Structural plasticity of single chromatin fibers revealed by torsional manipulation
Aurélien Bancaud, Natalia Conde e Silva, Maria Barbi, Gaudeline Wagner, Jean-François Allemand, Julien Mozziconacci, Christophe Lavelle, Vincent Croquette, Jean-Marc Victor, Ariel Prunell & Jean-Louis Viovy

General context

Chromatin is made of DNA wrapped in a regular manner around histone octamers, and is the major component of the cell nucleus. Its dynamics is essential for preserving the integrity of the genome, and for controlling the accessibility of DNA and thus the regulation of gene expression.

Presentation of the group

Our main research theme is the modelisation of the mechanical properties and statistical behavior of the chromatin fiber. The elastic behavior [Ben-Haïm et al 2001] and the topological properties [Barbi 2005] of model fibers have been obtained. This results allows us to make hypotheses on the functional dynamics of the chromatin fiber in vivo and its coupling with the chromosome dynamics [Mozziconacci et al 2006].
More recently, we started a collaboration with the team of J-L Viovy at the Institut Curie, about their magnetic tweezers experiments on single chromatin fibers. These revealed a resilient behavior in the torsion-extension chromatin response [Bancaud et al 2006]. We built a molecular and statistical model of the chromatin 3-D architecture, accounting for this resilient behavior of the fiber.

Objectives

This postdoc is supported by the french Research National Agency, in the frame of the collaboration with the team of J-L Viovy. The aim of next experiments will be the realization of more sophisticated techniques, aimed to get closer to physiologically relevant problems in the dynamic interactions of DNA, histones and proteins involved in chromatin dynamics. The postdoc will therefore participate to the theoretical analysis of these new experiments.

Conditions

Contacts