Abstract

Caulobacter Chromosome Chromosomal DNA must be highly compacted to fit within the tiny volume of the cell, while at the same time it must maintain a conformation that allows critical cellular processes access to the genome. Le et al. (p. 731 , published online 24 October) analyzed the structure of the circular chromosome in the prokaryote Caulobacter crescentus by using chromosome conformation capture and deep-sequencing. Highly self-interacting regions (chromosomal interaction domains, or CIDs) were observed—similar to the topologically associated domains previously seen in eukaryotes. Supercoiling helped to establish CIDs, and CID boundaries were defined by highly expressed genes. CIDs appeared to be established during or shortly after DNA replication, and could potentially facilitate chromosomal segregation by preventing newly replicated chromosomes from becoming entangled.