Sister chromatid cohesion: a simple concept with a complex reality.
In eukaryotes, the process of sister chromatid cohesion holds the two sister chromatids (the replicated chromosomes) together from DNA replication to the onset of chromosome segregation. Cohesion is mediated by cohesin, a four-subunit SMC (structural maintenance of chromosome) complex. Cohesin and cohesion are required for proper chromosome segregation, DNA repair, and gene expression. To carry out these functions, cohesion is regulated by elaborate mechanisms involving a growing list of cohesin auxiliary factors. These factors control the timing and position of cohesin binding to chromatin, activate chromatin-bound cohesin to become cohesive, and orchestrate the orderly dissolution of cohesion. The 45-nm ringlike architecture of soluble cohesin is compatible with dramatically different mechanisms for both chromatin binding and cohesion generation. Solving the mechanism of cohesion and its complex regulation presents significant challenges but offers the potential to provide important insights into higher-order chromosome organization and chromosome biology.
Onn
Itay
I
Howard Hughes Medical Institute, Carnegie Institution, Baltimore, Maryland 21218, USA. onn@ciwemb.edu
Heidinger-Pauli
Jill M
JM
Guacci
Vincent
V
Unal
Elçin
E
Koshland
Douglas E
DE
D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D002842:Chromatids / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000378:metabolism; D020090:Chromosome Segregation; D004260:DNA Repair; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D046911:Macromolecular Substances; D020033:Protein Isoforms; D000097722:Cohesins