Sur ce site

Sur le Web du CNRS

Accueil du site > Thèmes de recherche > Assembly of chromatin and ribosome biogenesis. Project leader : Philippe Bouvet. > Projets de Recherches > Assembly and organization of chromatin

Assembly and organization of chromatin

The alteration of the chromatin structure is an important step for the process of gene activation or silencing. Different factors may influence chromatin dynamics : the incorporation of histone variants on specific chromatin domains, the targeting of post-translational modification on histone, and the activity of chromatin remodelers. We are using in vitro biochemical approaches, in vivo assays and biophysical experiments in collaboration with the other teams of the Laboratory Joliot-Curie to study these different aspects of chromatin structure and dynamics. In particular, we are contributing in determining the role of the DNA sequences in nucleosome positioning and dynamics and the influence of histone variants on chromatin properties and in the regulation of gene expression.. We have previously shown that one histone chaperone was able to assist nucleosome dynamics by the remodelling machineries SWI/SNF and ACF. We are pursing this work studying the function of several histone chaperones on nucleosome dynamics in vitro and in vivo. The presence of chromatin domains within the cell nucleus seems to be also an important level of organization that may regulates basic processes such as DNA replication and transcription. The bioinformatic team of A. Arneodo in Joliot-Curie has identified numerous DNA replication origins. Using cell biology and the latest molecular biology techniques we are studying the organization of these origins within the cell nucleus. In summary, we contribute with the other teams of the laboratory Joliot-Curie to study diverse aspects of chromatin regulation using an interdisciplinary approach.

Legende du visual 1 :

A- The histone chaperone Nucleolin as a general chromatin modulating factor ? S FACT and nucleolin have been found to be involved either directly or through interaction with other factors in DNA replication, DNA repair and DNA recombination. These functions might be the consequences of their action on chromatin structure and dynamics.

B- The histone chaperone and FACT-like activities of nucleolin. In vitro, nucleolin destabilizes nucleosomes to promote the formation of hexasomes (loss of one H2A–H2B dimer) helping the passage of Pol II through chromatin templates. The histone chaperone activity of nucleolin helps the reformation of nucleosomal structures after the passage of the polymerase.