Europhys. Lett.
Volume 63, Number 6, September 2003
Page(s) 908 - 914
Section Interdisciplinary physics and related areas of science and technology
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00609-3
Europhys. Lett., 63 (6) , pp. 908-914 (2003)

Individual chromosomes as viscoelastic copolymers

S. Almagro1, 2, S. Dimitrov2, T. Hirano3, M. Vallade1 and D. Riveline1

1  Laboratoire de Spectrométrie Physique, UMR 5588, Université Joseph Fourier Saint-Martin, d'Hères, France
2  Institut Albert Bonniot, Unité INSERM 309 - La Tronche, France
3  Cold Spring Harbor Laboratory - Cold Spring Harbor, NY, USA

(Received 27 January 2003; accepted in final form 11 July 2003)

We report elastic measurements of individual chromosomes observed in vitro. Free fluctuations of shapes show that a chromosome can be seen as a copolymer, exhibiting rigid regions alternating with semi-flexible regions. We characterize this behavior and compare it with known biopolymers. We further show that the inner part of a chromosome exhibits viscoelasticity, as extracted by the loading rate dependence of the stretch modulus. Taken together, these data suggest an organization for the chromosome as a copolymer composed of an inner rigid core exhibiting viscoelasticity surrounded by an elastic soft envelope.

87.15.-v - Biomolecules: structure and physical properties.
82.35.Lr - Physical properties of polymers.
83.60.Bc - Linear viscoelasticity.

© EDP Sciences 2003