title: SHUGOSHINs and PATRONUS protect meiotic centromere cohesion in Arabidopsis thaliana.
abstract: In meiosis, chromosome cohesion is maintained by the cohesin complex, which is released in a two-step manner. At meiosis I, the meiosis-specific cohesin subunit Rec8 is cleaved by the protease Separase along chromosome arms, allowing homologous chromosome segregation. Next, in meiosis II, cleavage of the remaining centromere cohesin results in separation of the sister chromatids. In eukaryotes, protection of centromeric cohesion in meiosis I is mediated by SHUGOSHINs (SGOs). The Arabidopsis genome contains two SGO homologs. Here we demonstrate that Atsgo1 mutants show a premature loss of cohesion of sister chromatid centromeres at anaphase I and that AtSGO2 partially rescues this loss of cohesion. In addition to SGOs, we characterize PATRONUS which is specifically required for the maintenance of cohesion of sister chromatid centromeres in meiosis II. In contrast to the Atsgo1 Atsgo2 double mutant, patronus T-DNA insertion mutants only display loss of sister chromatid cohesion after meiosis I, and additionally show disorganized spindles, resulting in defects in chromosome segregation in meiosis. This leads to reduced fertility and aneuploid offspring. Furthermore, we detect aneuploidy in sporophytic tissue, indicating a role for PATRONUS in chromosome segregation in somatic cells. Thus, ploidy stability is preserved in Arabidopsis by PATRONUS during both meiosis and mitosis.
authors: Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Ghent, 9000, Belgium.
authors: Linda
authors: L
authors: Zamariola
authors: Nico
authors: N
authors: De Storme
authors: Katrijn
authors: K
authors: Vannerum
authors: Klaas
authors: K
authors: Vandepoele
authors: Susan J
authors: SJ
authors: Armstrong
authors: F Christopher H
authors: FC
authors: Franklin
authors: Danny
authors: D
authors: Geelen
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism / Q000502:physiology*; D002503:Centromere / Q000502:physiology*; D020090:Chromosome Segregation; D008540:Meiosis; D008938:Mitosis; D008941:Spindle Apparatus / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C000589332:SGO1 protein, Arabidopsis; C000589333:SGO2 protein, Arabidopsis; C000589331:patronus protein, Arabidopsis
keywords: Arabidopsis thaliana; centromere; chromosome segregation; cohesion; meiosis; sister chromatids