Multiscale Structuring of the E. coli Chromosome by Nucleoid-Associated and Condensin Proteins

Non programmé
20m

Orateur

Virginia Lioy (I2BC)

Description

As in Eukaryotes, bacterial genomes must be accurately folded to ensure their proper function. Bacterial genetic information is generally carried on a single circular chromosome with a unique origin of replication from which two replication forks proceed bidirectionally to the opposite terminus region. Here we investigated the higher-order genome architecture of the model bacteria Escherichia coli. We show that the chromosome is partitioned into two structurally distinct entities through a complex and intertwined network of contacts: the replication terminus (ter) region and the rest of the chromosome. Outside ter, the condensin MukBEF and the ubiquitous nucleoid-associated protein (NAP) HU promote DNA contacts in the megabase range. Within ter, the MatP protein prevents MukBEF activity and contacts are restricted to ~280 kb creating a domain with unique structural properties. We also show how other NAPs contribute to nucleoid organization, such as H-NS that constrains and insulates short-range interactions. Combined, these results reveal the contributions of major, evolutionary conserved proteins in a bacterial chromosome organization.

Auteurs principaux

Virginia Lioy (I2BC) Axel Cournac (Institut Pasteur) Stéphane Duigou (I2BC) Olivier Espéli (College de France) Romain Koszul (Institut Pasteur) Frédéric Boccard (I2BC)

Documents de présentation

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