title: Non-SMC Element 2 (NSMCE2) of the SMC5/6 Complex Helps to Resolve Topological Stress.
abstract: The structural maintenance of chromosomes (SMC) protein complexes shape and regulate the structure and dynamics of chromatin, thereby controlling many chromosome-based processes such as cell cycle progression, differentiation, gene transcription and DNA repair. The SMC5/6 complex is previously described to promote DNA double-strand breaks (DSBs) repair by sister chromatid recombination, and found to be essential for resolving recombination intermediates during meiotic recombination. Moreover, in budding yeast, SMC5/6 provides structural organization and topological stress relief during replication in mitotically dividing cells. Despite the essential nature of the SMC5/6 complex, the versatile mechanisms by which SMC5/6 functions and its molecular regulation in mammalian cells remain poorly understood. By using a human osteosarcoma cell line (U2OS), we show that after the CRISPR-Cas9-mediated removal of the SMC5/6 subunit NSMCE2, treatment with the topoisomerase II inhibitor etoposide triggered an increased sensitivity in cells lacking NSMCE2. In contrast, NSMCE2 appeared not essential for a proper DNA damage response or cell survival after DSB induction by ionizing irradiation (IR). Interestingly, by way of immunoprecipitations (IPs) and mass spectrometry, we found that the SMC5/6 complex physically interacts with the DNA topoisomerase II α (TOP2A). We therefore propose that the SMC5/6 complex functions in resolving TOP2A-mediated DSB-repair intermediates generated during replication.
authors: Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. emma.verver@nikon.com.
authors: Dideke E
authors: DE
authors: Verver
authors: Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. y.zheng@amc.uva.nl.
authors: Yi
authors: Y
authors: Zheng
authors: Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. d.speijer@amc.uva.nl.
authors: Dave
authors: D
authors: Speijer
authors: Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. r.a.hoebe@amc.uva.nl.
authors: Ron
authors: R
authors: Hoebe
authors: Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam, 1090 GE Amsterdam, The Netherlands. h.l.dekker@uva.nl.
authors: Henk L
authors: HL
authors: Dekker
authors: Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. s.repping@amc.uva.nl.
authors: Sjoerd
authors: S
authors: Repping
authors: Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. j.stap@amc.uva.nl.
authors: Jan
authors: J
authors: Stap
authors: Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. g.hamer@amc.uva.nl.
authors: Geert
authors: G
authors: Hamer
mesh_terms: D000951:Antigens, Neoplasm / Q000378:metabolism; D064113:CRISPR-Cas Systems; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D002868:Chromosomal Proteins, Non-Histone; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005047:Etoposide / Q000009:adverse effects; D006801:Humans; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D060066:Protein Interaction Maps; D059005:Topoisomerase II Inhibitors / Q000009:adverse effects
chemical_list: D000951:Antigens, Neoplasm; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; C432931:SMC5 protein, human; C432932:SMC6 protein, human; D059005:Topoisomerase II Inhibitors; D005047:Etoposide; D004250:DNA Topoisomerases, Type II; C000618811:TOP2A protein, human; D008025:Ligases; C503501:NSMCE2 protein, human
keywords: CRISPR-Cas9; DNA double-strand breaks (DSBs); Ionizing Radiation (IR); Non-SMC Element 2 (NSMCE2); Structural Maintenance of Chromosomes 5/6 complex (SMC5/6); Topoisomerase II α (TOP2A)