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bioRxiv · 10.1101/513960

Scc2 counteracts a Wapl-independent mechanism that releases cohesin from chromosomes during G1 but is unnecessary during S phase for establishing cohesion

Nasmyth, K. A.·Srinivasan, M.·Petela, N. J.·Scheinost, J. C.·Collier, J.·Voulgaris, M.·Brunet-Roig, M.·Beckouët, F.·Hu, B.
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Abstract

Cohesins association with chromosomes is determined by loading dependent on the Scc2/4 complex and release due to Wapl. We show here that Scc2/4 is not merely a loading complex and that it actively maintains cohesin on chromosomes during G1. It does so by blocking a Wapl-independent release reaction that requires opening the cohesin ring at its Smc3/Scc1 interface as well as the D loop of Smc1s ATPase. The Wapl-independent release mechanism is switched off as cells activate Cdk1 and enter G2/M and cannot be turned back on without cohesins dissociation from chromosomes. The latter phenomenon enabled us to show that cohesin that has already captured DNA in a Scc2-dependent manner before replication no longer requires Scc2 to capture sister DNAs during S phase.

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Nasmyth, K. A., Srinivasan, M., Petela, N. J., Scheinost, J. C., Collier, J., Voulgaris, M., Brunet-Roig, M., Beckouët, F., Hu, B.. 2019-01-09. Scc2 counteracts a Wapl-independent mechanism that releases cohesin from chromosomes during G1 but is unnecessary during S phase for establishing cohesion. https://doi.org/10.1101/513960

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