Condensin aids sister chromatid decatenation by topoisomerase II.
The condensin complex is a key determinant of mitotic chromosome architecture. In addition, condensin promotes resolution of sister chromatids during anaphase, a function that is conserved from prokaryotes to human. Anaphase bridges observed in cells lacking condensin are reminiscent of chromosome segregation failure after inactivation of topoisomerase II (topo II), the enzyme that removes catenanes persisting between sister chromatids following DNA replication. Circumstantial evidence has linked condensin to sister chromatid decatenation but, because of the difficulty of observing chromosome catenation, this link has remained indirect. Alternative models for how condensin facilitates chromosome resolution have been put forward. Here, we follow the catenation status of circular minichromosomes of three sizes during the Saccharomyeces cerevisiae cell cycle. Catenanes are produced during DNA replication and are for the most part swiftly resolved during and following S-phase, aided by sister chromatid separation. Complete resolution, however, requires the condensin complex, a dependency that becomes more pronounced with increasing chromosome size. Our results provide evidence that condensin prevents deleterious anaphase bridges during chromosome segregation by promoting sister chromatid decatenation.
Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London WC2A 3LY, UK.
Adrian
A
Charbin
Céline
C
Bouchoux
Frank
F
Uhlmann
D000251:Adenosine Triphosphatases / Q000378:metabolism / Q000502:physiology*; D002453:Cell Cycle / Q000235:genetics; D002842:Chromatids / Q000737:chemistry / Q000201:enzymology*; D020090:Chromosome Segregation; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D043864:DNA, Catenated / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D046912:Multiprotein Complexes / Q000378:metabolism / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics
D043864:DNA, Catenated; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; C108312:condensin complexes; D000251:Adenosine Triphosphatases; D004250:DNA Topoisomerases, Type II