Int. J. Dev. Biol. 65: 487 - 496 (2021)

https://doi.org/10.1387/ijdb.200313jk

Vol 65, Issue 7-8-9

Mitotic timing is differentially controlled by A- and B-type cyclins and by CDC6 associated with a bona fide CDK inhibitor Xic1 in Xenopus laevis cell-free extract

Original Article | Published: 10 September 2021

Mohammed El Dika¹, Lisa Wechselberger¹, Bilal Djeghout^1,3, Djamel Eddine Benouareth^1,3, Krystyna Jęderka⁴, Sławomir Lewicki^4,5, Robert Zdanowski⁶, Claude Prigent^1,7, Malgorzata Kloc*^,8,9,10 and Jacek Z. Kubiak*^,1,2,4,11

¹Univ Rennes, UMR 6290, CNRS, Institute of Genetics and Development of Rennes - IGDR, Cell Cycle Group, Faculty of Medicine, Rennes, France, ²Univ Rennes, UMR 6290, CNRS, Institute of Genetics and Development of Rennes - IGDR, Dynamics and Mechanics of Epithelia Group, Faculty of Medicine, Rennes, France, ³Biology Department, University 8 mai 1945, Guelma, Algeria, ⁴Department of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), Warsaw, Poland, ⁵Department of Molecular Biology, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Jastrzebiec, Magdalenka, Poland, ⁶Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine - WIM, Warsaw, Poland, ⁷CRBM, UMR 5237, CNRS, Université de Montpellier, Cell Cycle Group, Montpellier, France, ⁸The Houston Methodist Research Institute, Houston, Texas, USA, ⁹The Houston Methodist Hospital, Department of Surgery, Houston, Texas, USA, ¹⁰The University of Texas, M.D. Anderson Cancer Center, Department of Genetics, Houston Texas, USA, ¹¹Departement of Experimental Embryology, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Jastrzębiec, Magdalenka, Poland

Abstract

The timing of the M-phase is precisely controlled by a CDC6-dependent mechanism inhibiting the mitotic histone H1 kinase. Here, we describe the differential regulation of the dynamics of this mitotic kinase activity by exogenous cyclin A or cyclin B in the Xenopus laevis cycling extracts. We show that the experimental increase in cyclin A modifies only the level of histone H1 kinase activity, while the cyclin B increase modifies two parameters: histone H1 kinase activity and the timing of its full activation, which is accelerated. On the other hand, the cyclin A depletion significantly delays full activation of histone H1 kinase. However, when CDC6 is added to such an extract, it inhibits cyclin B-associated histone H1 kinase, but does not modify the mitotic timing in the absence of cyclin A. Further, we show via p9 co-precipitation with Cyclin-Dependent Kinases (CDKs), that both CDC6 and the bona fide CDK1 inhibitor Xic1 associate with the mitotic CDKs. Finally, we show that the Xic1 temporarily separates from the mitotic CDKs complexes during the peak of histone H1 kinase activity. These data show the differential coordination of the M-phase progression by cyclin A- and cyclin B-dependent CDKs, confirm the critical role of the CDC6-dependent histone H1 kinase inhibition in this process, and show that CDC6 acts differentially through the cyclin B- and cyclin A-associated CDKs. This CDC6- and cyclins-dependent mechanism likely depends on the precisely regulated association of Xic1 with the mitotic CDKs complexes. We postulate that: i. the dissociation of Xic1 from the CDKs complexes allows the maximal activation of CDK1 during the M-phase, ii. the switch between cyclin A- and cyclin B-CDK inhibition upon M-phase initiation may be responsible for the diauxic growth of mitotic histone H1 kinase activity.

Keywords

Mitosis, cyclin, CDK1, CDC6, Xic1