SMC complexes differentially compact mitotic chromosomes according to genomic context
Program in Systems Biology; Department of Biochemistry and Molecular Pharmacology
Computational Biology | Genomics | Structural Biology | Systems Biology
Structural maintenance of chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modelling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids, while condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate that this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead, it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes.
Chromosome condensation, Chromosome conformation capture-based methods, Cohesion, DNA sequencing, Mitosis
DOI of Published Version
Nat Cell Biol. 2017 Sep;19(9):1071-1080. doi: 10.1038/ncb3594. Epub 2017 Aug 21. Link to article on publisher's site
Nature cell biology
Schalbetter, Stephanie Andrea; Goloborodko, Anton; Fudenberg, Geoffrey; Belton, Jon-Matthew; Miles, Catrina; Yu, Miao; Dekker, Job; Mirny, Leonid; and Baxter, Jonathan, "SMC complexes differentially compact mitotic chromosomes according to genomic context" (2017). Program in Systems Biology Publications and Presentations. 117.