Insights on the regulatory principles of genome organization in unicellular microorganisms
Romain Koszul (Institut Pasteur)
Chromosomes of a broad range of kingdoms, from bacteria to mammals, are structured by large topological domains, whose precise functional roles and regulatory mechanisms remain elusive. Using chromosome conformation capture technology, we unraveled the higher-order organization of the Bacillus subtilis, Escherichia coli and Vibrio cholerae genomes, in a variety of growth and mutant conditions. Different types of topological domains were found to structure these chromosomes, ranging from a few dozens to a thousand kb. We show that the matP/matS and parB/parS systems generate specific types of topological structures, regulated by replication and cell cycle progression. We have also functionally characterized some of the global organizational principles of these domains, in link with replication/segregation during the cell cycle. Overall, the comparative analysis of these different species provide striking insights on the diversity of the regulatory mechanisms of genome structure of the bacterial world. In addition, I will also present and discuss recent data obtained during the cell cycle of the eukaryotic species Saccharomyces cerevisiae.