Structuring the E. coli chromosome into Macrodomains – SECOM

The size of genomes compared to cell dimensions imposes a necessity of DNA condensation. Although DNA is highly condensed, it should nonetheless allow gene expression and accurate segregation of genetic material to daughter cells at each cell division. We have shown that condensation of the chromosome in the bacterial model, Escherichia coli, relies on the existence of large insulated regions called Macrodomains (MD) that coexist with 2 regions called Non-Structured Regions. We have recently identified one factor specifying the properties of one MD; thus we will be able to elucidate the molecular mechanisms responsible for the condensation and insulation in the cell of large chromosomal regions. Characterization of the processes governing the structuring of other MDs should enable us to determine whether other strategies are operant in E. coli cells. Affecting macrodomain formation will enable us to highlight the rationale of chromosome organization into macrodomains and Non-structured regions and characterize chromosome management during the cell cycle.