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Meiotic chromosome structures constrain and respond to designation of crossover sites

机译:减数分裂的染色体结构限制并响应交叉位点的指定

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摘要

Crossover recombination events between homologous chromosomes are required to form chiasmata, temporary connections between homologues that ensure their proper segregation at meiosis I. Despite this requirement for crossovers and an excess of the doublestrand DNA breaks that are the initiating events for meiotic recombination, most organisms make very few crossovers per chromosome pair. Moreover, crossovers tend to inhibit the formation of other crossovers nearby on the same chromosome pair, a poorly understood phenomenon known as crossover interference. Here we show that the synaptonemal complex, a meiosis-specific structure that assembles between aligned homologous chromosomes, both constrains and is altered by crossover recombination events. Using a cytological marker of crossover sites in Caenorhabditis elegans, we show that partial depletion of the synaptonemal complex central region proteins attenuates crossover interference, increasing crossovers and reducing the effective distance over which interference operates, indicating that synaptonemal complex proteins limit crossovers. Moreover, we show that crossovers are associated with a local 0.4-0.5-micrometre increase in chromosome axis length. We propose that meiotic crossover regulation operates as a self-limiting system in which meiotic chromosome structures establish an environment that promotes crossover formation, which in turn alters chromosome structure to inhibit other crossovers at additional sites.%在减数分裂过程中(此时在染色体被分离到两 个子细胞中之前其数量翻倍),同源染色体通 过链的交换而在一个"X-结构"或一次交叉中 被保持在一起。交叉是由程序化的双联断裂启 动的,而且一个断裂一旦形成,其附近的其他 断裂的形成就会通过一个被称为"交叉干涉" 的过程被抑制。Anne Villeneuve及同事发现, "联会丝蛋白"(它们在成对的同源染色体周 围形成一个涂层)负责这种干涉。另外,一个 交叉一旦出现,局部染色体结构就会被改变和 加长,这些变化也许还有助于抑制进一步的交 叉启动。
机译:同源染色体之间的交换重组事件需要形成chiasmata,即同源物之间的临时连接,以确保它们在减数分裂I时正确分离。尽管存在交换的要求和过多的双链DNA断裂,这是减数分裂重组的起始事件,但大多数生物体每个染色体对的交换很少。而且,交叉倾向于抑制同一染色体对附近其他交叉的形成,这是人们所知甚少的现象,称为交叉干扰。在这里,我们显示突触复合物,一种减数分裂特异的结构,在对齐的同源染色体之间组装,既受约束,又被交叉重组事件所改变。使用秀丽隐杆线虫中的交叉位点的细胞学标记,我们显示突触复合体中心区域蛋白的部分耗竭减弱了交叉干扰,增加了交叉,并减少了干扰作用的有效距离,表明突触复合蛋白限制了交叉。此外,我们表明交叉与染色体轴长度的局部0.4-0.5微米增加有关。我们提议减数分裂调控是一种自我限制的系统,其中减数分裂的染色体结构建立了一个促进交换形成的环境,从而改变了染色体结构以抑制其他位点的其他交换。在染色体被分离到两个个子细胞中之前其数量翻倍),近似染色体通过链的交换而在一个“ X-结构”或一次交叉中被保持在一起。交叉是由程序化的双联断裂安妮·维伦纽夫及同事发现,“联会丝蛋白”(它们在成对对)另外,一个交叉重新出现,局部染色体结构就会被改变和加长,这些变化也许还能抑制进一步的交叉启动。

著录项

  • 来源
    《Nature》 |2013年第7473期|703-706a2|共5页
  • 作者单位

    Department of Developmental Biology, Stanford University, School of Medicine, Stanford, California 94305, USA;

    Howard Hughes Medical Institute and Department of Molecular and Cell Biology,University of California at Berkeley, Berkeley, California 94720, USA;

    Howard Hughes Medical Institute and Department of Molecular and Cell Biology,University of California at Berkeley, Berkeley, California 94720, USA;

    Department of Developmental Biology, Stanford University, School of Medicine, Stanford, California 94305, USA,Department of Genetics, Stanford University, School of Medicine, Stanford, California 94305, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
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