PIASγ is required for faithful chromosome segregation in human cells

Laura A. Díaz-Martínez, Juan F. Giménez-Abián, Yoshiaki Azuma, Vincent Guacci, Gonzalo Giménez-Martín, Lorene M. Lanier, Duncan J. Clarke

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Background. The precision of the metaphase-anaphase transition ensures stable genetic inheritance. The spindle checkpoint blocks anaphase onset until the last chromosome biorients at metaphase plate, then the bonds between sister chromatids are removed and disjoined chromatids segregate to the spindle poles. But, how sister separation is triggered is not fully understood. Principal Findings. We identify PIASγ as a human E3 sumo ligase required for timely and efficient sister chromatid separation. In cells lacking PIASγ, normal metaphase plates form, but the spindle checkpoint is activated, leading to a prolonged metaphase block. Sister chromatids remain cohered even if cohesin is removed by depletion of hSgo1, because DNA catenations persist at centromeres. PIASγ-depleted cells cannot properly localize Topoisomerase II at centromeres or in the cores of mitotic chromosomes, providing a functional link between PIASc and Topoisomerase II. Conclusions. PIASγ directs Topoisomerase II to specific chromosome regions that require efficient removal of DNA catenations prior to anaphase. The lack of this activity activates the spindle checkpoint, protecting cells from non-disjunction. Because DNA catenations persist without PIASγ in the absence of cohesin, removal of catenations and cohesin rings must be regulated in parallel.

Original languageEnglish (US)
Article numbere53
JournalPloS one
Issue number1
StatePublished - Dec 20 2006


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