title: Meiotic prophase roles of Rec8 in crossover recombination and chromosome structure.
abstract: Rec8 is a prominent component of the meiotic prophase chromosome axis that mediates sister chromatid cohesion, homologous recombination and chromosome synapsis. Here, we explore the prophase roles of Rec8. (i) During the meiotic divisions, Rec8 phosphorylation mediates its separase-mediated cleavage. We show here that such cleavage plays no detectable role for chromosomal events of prophase. (ii) We have analyzed in detail three rec8 phospho-mutants, with 6, 24 or 29 alanine substitutions. A distinct 'separation of function' phenotype is revealed. In the mutants, axis formation and recombination initiation are normal, as is non-crossover recombination; in contrast, crossover (CO)-related events are defective. Moreover, the severities of these defects increase coordinately with the number of substitution mutations, consistent with the possibility that global phosphorylation of Rec8 is important for these effects. (iii) We have analyzed the roles of three kinases that phosphorylate Rec8 during prophase. Timed inhibition of Dbf4-dependent Cdc7 kinase confers defects concordant with rec8 phospho-mutant phenotypes. Inhibition of Hrr25 or Cdc5/polo-like kinase does not. Our results suggest that Rec8's prophase function, independently of cohesin cleavage, contributes to CO-specific events in conjunction with the maintenance of homolog bias at the leptotene/zygotene transition of meiotic prophase.
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Yoon
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Min-Su
authors.initials: MS
authors.lastname: Lee
authors.affiliation: Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna 1030, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Xaver
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Liangran
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Soo-Gil
authors.initials: SG
authors.lastname: Hong
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Yoon-Ju
authors.initials: YJ
authors.lastname: Kong
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Hong-Rae
authors.initials: HR
authors.lastname: Cho
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Kleckner
authors.affiliation: Department of Life Science, Chung-Ang University, Seoul 156-756, Korea kpkim@cau.ac.kr.
authors.forename: Keun P
authors.initials: KP
authors.lastname: Kim
mesh_terms: D000483:Alleles; D018797:Cell Cycle Proteins / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D002874:Chromosome Mapping; D022004:Chromosome Structures; D003434:Crossing Over, Genetic; D053903:DNA Breaks, Double-Stranded; D053837:DNA Cleavage; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D008938:Mitosis / Q000235:genetics*; D046912:Multiprotein Complexes; D009154:Mutation; D010641:Phenotype; D010766:Phosphorylation; D011418:Prophase / Q000235:genetics*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; C502898:REC8 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D044767:Ubiquitin-Protein Ligases; C489404:CDC7 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C081927:CDC5 protein, S cerevisiae; D048369:MAP Kinase Kinase 1; C523917:Zip3 protein, S cerevisiae