Kinetic control of gene expression by chromatin remodeling
Prof. Dr. Ralf Blossey (Interdisciplinary Research Institute CNRS, Lille)
Chromatin remodeling is the ATP-dependent change of chromatin structure performed by dedicated motor complexes acting on nucleosomal substrates. I give a general introduction into chromatin remodeling and propose a mechanism by which the remodelers are targeted to their substrates via a kinetic proofreading scheme. This - scenario has recently found experimental support for the ISWI-family of remodelers which are mainly involved in gene repression by the formation of regularly positioned nucleosomes. In particular we have considered ACF, a member of the ISWI-family which positions nucleosomes as a bidirectional motor. We have built statistical physics models for the positioning capacities of the motor and applied them to the positioning of single nucleosomes and nucleosomal arrays. Our findings show that chromatin remodeling can lead to pronounced nucleosomal ordering beyond the usually considered statistical positioning effects.