Defined chromosome structure in the genome-reduced bacterium Mycoplasma pneumoniae.

ABSTRACT: DNA-binding proteins are central regulators of chromosome organization; however, in genome-reduced bacteria their diversity is largely diminished. Whether the chromosomes of such bacteria adopt defined three-dimensional structures remains unexplored. Here we combine Hi-C and super-resolution microscopy to determine the structure of the Mycoplasma pneumoniae chromosome at a 10?kb resolution. We find a defined structure, with a global symmetry between two arms that connect opposite poles, one bearing the chromosomal Ori and the other the midpoint. Analysis of local structures at a 3?kb resolution indicates that the chromosome is organized into domains ranging from 15 to 33?kb. We provide evidence that genes within the same domain tend to be co-regulated, suggesting that chromosome organization influences transcriptional regulation, and that supercoiling regulates local organization. This study extends the current understanding of bacterial genome organization and demonstrates that a defined chromosomal structure is a universal feature of living systems.

SUBMITTER: Trussart M 

PROVIDER: S-EPMC5344976 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature