Distinct functions of S. pombe Rec12 (Spo11) protein and Rec12-dependent crossover recombination (chiasmata) in meiosis I; and a requirement for Rec12 in meiosis II.
Distinct functions of S. pombe Rec12 (Spo11) protein and Rec12-dependent crossover recombination (chiasmata) in meiosis I; and a requirement for Rec12 in meiosis II.
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DOI：
10.1186/1475-9268-1-1
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发表时间：
2002-09-19
期刊：
影响因子：
--
通讯作者：
Wahls WP
中科院分区：
文献类型：
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作者：
Sharif WD;Glick GG;Davidson MK;Wahls WP
在大多数生物中，减数分裂I期间适当的减数分裂染色体分离与交叉重组结构的存在密切相关；重组缺陷突变体缺乏交叉，减数分裂I不分离。我们报道这些功能在裂殖酵母中是可分离的。内含子定位和表达研究证实，Rec12是Spo11/Top6A拓扑异构酶家族的成员，是形成减数分裂dsDNA断裂和重组所必需的。Rec12-117、rec12-D15(空)和rec12-Y98F(活性位点)突变体缺乏大部分交叉重组，染色体异常分离产生非整倍体减数分裂产物。因为S.pombe只包含三对染色体，所以这些非整倍体产物中的许多都是活的。根据二倍体减数分裂产物中着丝粒连锁标记的遗传模式，推测了染色体异常分离的类型。Rec12-117和rec12-D15突变体在减数分裂I和减数分裂II期间都表现出分离错误。值得注意的是，rec12-Y98F(活性位点)突变体表现出基本正常的减数分裂I分离模式，但仍然表现出减数分裂II分离错误。Rec12是一种345个氨基酸的蛋白质，是大多数交叉重组所必需的，也是减数分裂I期间染色体交叉分离所必需的。此外，具有催化活性的Rec12还参与减数分裂I期间染色体分离的备用分配(交叉)系统。此外，具有催化活性的Rec12还介导了减数分裂II期间染色体忠实等式分离所需的一些信号。
In most organisms proper reductional chromosome segregation during meiosis I is strongly correlated with the presence of crossover recombination structures (chiasmata); recombination deficient mutants lack crossovers and suffer meiosis I nondisjunction. We report that these functions are separable in the fission yeast Schizosaccharomyces pombe. Intron mapping and expression studies confirmed that Rec12 is a member of the Spo11/Top6A topoisomerase family required for the formation of meiotic dsDNA breaks and recombination. rec12-117, rec12-D15 (null), and rec12-Y98F (active site) mutants lacked most crossover recombination and chromosomes segregated abnormally to generate aneuploid meiotic products. Since S. pombe contains only three chromosome pairs, many of those aneuploid products were viable. The types of aberrant chromosome segregation were inferred from the inheritance patterns of centromere linked markers in diploid meiotic products. The rec12-117 and rec12-D15 mutants manifest segregation errors during both meiosis I and meiosis II. Remarkably, the rec12-Y98F (active site) mutant exhibited essentially normal meiosis I segregation patterns, but still exhibited meiosis II segregation errors. Rec12 is a 345 amino acid protein required for most crossover recombination and for chiasmatic segregation of chromosomes during meiosis I. Rec12 also participates in a backup distributive (achiasmatic) system of chromosome segregation during meiosis I. In addition, catalytically-active Rec12 mediates some signal that is required for faithful equational segregation of chromosomes during meiosis II.