title: Sisters unbound is required for meiotic centromeric cohesion in Drosophila melanogaster.
abstract: Regular meiotic chromosome segregation requires sister centromeres to mono-orient (orient to the same pole) during the first meiotic division (meiosis I) when homologous chromosomes segregate, and to bi-orient (orient to opposite poles) during the second meiotic division (meiosis II) when sister chromatids segregate. Both orientation patterns require cohesion between sister centromeres, which is established during meiotic DNA replication and persists until anaphase of meiosis II. Meiotic cohesion is mediated by a conserved four-protein complex called cohesin that includes two structural maintenance of chromosomes (SMC) subunits (SMC1 and SMC3) and two non-SMC subunits. In Drosophila melanogaster, however, the meiotic cohesion apparatus has not been fully characterized and the non-SMC subunits have not been identified. We have identified a novel Drosophila gene called sisters unbound (sunn), which is required for stable sister chromatid cohesion throughout meiosis. sunn mutations disrupt centromere cohesion during prophase I and cause high frequencies of non-disjunction (NDJ) at both meiotic divisions in both sexes. SUNN co-localizes at centromeres with the cohesion proteins SMC1 and SOLO in both sexes and is necessary for the recruitment of both proteins to centromeres. Although SUNN lacks sequence homology to cohesins, bioinformatic analysis indicates that SUNN may be a structural homolog of the non-SMC cohesin subunit stromalin (SA), suggesting that SUNN may serve as a meiosis-specific cohesin subunit. In conclusion, our data show that SUNN is an essential meiosis-specific Drosophila cohesion protein.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Badri
authors.initials: B
authors.lastname: Krishnan
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Thomas
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Rihui
authors.initials: R
authors.lastname: Yan
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee 37996 Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996 Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831.
authors.forename: Igor B
authors.initials: IB
authors.lastname: Zhulin
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee 37996 bdmckee@utk.edu.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: McKee
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry; D002503:Centromere / Q000378:metabolism*; D002842:Chromatids / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry; D020090:Chromosome Segregation; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D005260:Female; D017344:Genes, Insect; D056426:Genetic Loci; D008297:Male; D008540:Meiosis; D049469:Meiotic Prophase I; D009154:Mutation / Q000235:genetics; D009630:Nondisjunction, Genetic; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D012730:Sex Chromosomes; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism; D000097722:Cohesins
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D000097722:Cohesins
keywords: Drosophila melanogaster; Sisters Unbound (SUNN); centromere; chromosome; cohesion; meiosis