title: Conditional mutation of Smc5 in mouse embryonic stem cells perturbs condensin localization and mitotic progression.
abstract: Correct duplication of stem cell genetic material and its appropriate segregation into daughter cells are requisites for tissue, organ and organism homeostasis. Disruption of stem cell genomic integrity can lead to developmental abnormalities and cancer. Roles of the Smc5/6 structural maintenance of chromosomes complex in pluripotent stem cell genome maintenance have not been investigated, despite its important roles in DNA synthesis, DNA repair and chromosome segregation as evaluated in other model systems. Using mouse embryonic stem cells (mESCs) with a conditional knockout allele of Smc5, we showed that Smc5 protein depletion resulted in destabilization of the Smc5/6 complex, accumulation of cells in G2 phase of the cell cycle and apoptosis. Detailed assessment of mitotic mESCs revealed abnormal condensin distribution and perturbed chromosome segregation, accompanied by irregular spindle morphology, lagging chromosomes and DNA bridges. Mutation of Smc5 resulted in retention of Aurora B kinase and enrichment of condensin on chromosome arms. Furthermore, we observed reduced levels of Polo-like kinase 1 at kinetochores during mitosis. Our study reveals crucial requirements of the Smc5/6 complex during cell cycle progression and for stem cell genome maintenance.
authors.affiliation: Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
authors.forename: Marina V
authors.initials: MV
authors.lastname: Pryzhkova
authors.affiliation: Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA pjordan8@jhu.edu.
authors.forename: Philip W
authors.identifier: http://orcid.org/0000-0003-4890-2647
authors.initials: PW
authors.lastname: Jordan
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D064107:Aurora Kinase B / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D020090:Chromosome Segregation / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000502:physiology*; D051379:Mice; D008938:Mitosis; D046912:Multiprotein Complexes / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000502:physiology; D000097869:Polo-Like Kinase 1
chemical_list: D000251:Adenosine Triphosphatases; D064107:Aurora Kinase B; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C000613261:SMC5 protein, mouse; C583968:SMC6 protein, mouse; C108312:condensin complexes; C576924:Aurkb protein, mouse
keywords: Apoptosis; Chromosome segregation; Genomic integrity; Mouse embryonic stem cells; Pluripotency; Smc5; Smc6