title: Dynamic localization of SMC5/6 complex proteins during mammalian meiosis and mitosis suggests functions in distinct chromosome processes.
abstract: Four members of the structural maintenance of chromosome (SMC) protein family have essential functions in chromosome condensation (SMC2/4) and sister-chromatid cohesion (SMC1/3). The SMC5/6 complex has been implicated in chromosome replication, DNA repair and chromosome segregation in somatic cells, but its possible functions during mammalian meiosis are unknown. Here, we show in mouse spermatocytes that SMC5 and SMC6 are located at the central region of the synaptonemal complex from zygotene until diplotene. During late diplotene both proteins load to the chromocenters, where they colocalize with DNA Topoisomerase IIα, and then accumulate at the inner domain of the centromeres during the first and second meiotic divisions. Interestingly, SMC6 and DNA Topoisomerase IIα colocalize at stretched strands that join kinetochores during the metaphase II to anaphase II transition, and both are observed on stretched lagging chromosomes at anaphase II following treatment with Etoposide. During mitosis, SMC6 and DNA Topoisomerase IIα colocalize at the centromeres and chromatid axes. Our results are consistent with the participation of SMC5 and SMC6 in homologous chromosome synapsis during prophase I, chromosome and centromere structure during meiosis I and mitosis and, with DNA Topoisomerase IIα, in regulating centromere cohesion during meiosis II.
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Gómez
authors.forename: Philip W
authors.initials: PW
authors.lastname: Jordan
authors.forename: Alberto
authors.initials: A
authors.lastname: Viera
authors.forename: Manfred
authors.initials: M
authors.lastname: Alsheimer
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fukuda
authors.forename: Rolf
authors.initials: R
authors.lastname: Jessberger
authors.forename: Elena
authors.initials: E
authors.lastname: Llano
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Pendás
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Handel
authors.forename: José A
authors.initials: JA
authors.lastname: Suja
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002503:Centromere / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation / Q000235:genetics*; D005854:Germ Cells; D006801:Humans; D008322:Mammals; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D008938:Mitosis / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C432931:SMC5 protein, human
keywords: Centromere; DNA Topoisomerase IIα; Meiosis; Mitosis; Mouse; SMC5; SMC6; Synaptonemal complex