Title

Condensin promotes the juxtaposition of DNA flanking its loading site in Bacillus subtilis

UMMS Affiliation

Program in Systems Biology; Department of Biochemistry and Molecular Pharmacology

Date

8-1-2015

Document Type

Article

Disciplines

Biochemistry, Biophysics, and Structural Biology | Genetics and Genomics | Systems Biology

Abstract

SMC condensin complexes play a central role in compacting and resolving replicated chromosomes in virtually all organisms, yet how they accomplish this remains elusive. In Bacillus subtilis, condensin is loaded at centromeric parS sites, where it encircles DNA and individualizes newly replicated origins. Using chromosome conformation capture and cytological assays, we show that condensin recruitment to origin-proximal parS sites is required for the juxtaposition of the two chromosome arms. Recruitment to ectopic parS sites promotes alignment of large tracks of DNA flanking these sites. Importantly, insertion of parS sites on opposing arms indicates that these "zip-up" interactions only occur between adjacent DNA segments. Collectively, our data suggest that condensin resolves replicated origins by promoting the juxtaposition of DNA flanking parS sites, drawing sister origins in on themselves and away from each other. These results are consistent with a model in which condensin encircles the DNA flanking its loading site and then slides down, tethering the two arms together. Lengthwise condensation via loop extrusion could provide a generalizable mechanism by which condensin complexes act dynamically to individualize origins in B. subtilis and, when loaded along eukaryotic chromosomes, resolve them during mitosis.

Rights and Permissions

Citation: Genes Dev. 2015 Aug 1;29(15):1661-75. doi: 10.1101/gad.265876.115. Link to article on publisher's site

Related Resources

Link to Article in PubMed

Journal Title

Genes and development

PubMed ID

26253537