Abstract

Meiosis produces the haploid gametes required by all sexually-reproducing organisms, occurring in specific temperature ranges in different organisms. However, how meiotic thermotolerance is regulated remains largely unknown. Using the model organism Caenorhabditis elegans, here, we identified the synaptonemal complex (SC) protein SYP-5 as a critical regulator of meiotic thermotolerance. syp-5-null mutants maintained a high percentage of viable progeny at 20 °C but produced significantly fewer viable progeny at 25 °C, a permissive temperature in wild-type worms. Cytological analysis of meiotic events in the mutants revealed that while SC assembly and disassembly as well as DNA double-strand break repair kinetics were not affected by the elevated temperature, crossover designation and bivalent formation were significantly affected. More severe homolog segregation errors were also observed at the elevated temperature. A temperature switching assay revealed that late meiotic prophase events were not temperature-sensitive and that meiotic defects during pachytene stage were responsible for the reduced viability of syp-5 mutants at the elevated temperature. Moreover, SC polycomplex formation and hexanediol sensitivity analysis suggested that SYP-5 was required for the normal properties of the SC, and charge-interacting elements in SC components were involved in regulating meiotic thermotolerance. Together, these findings provide a novel molecular mechanism for meiotic thermotolerance regulation.

中文翻译：

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SYP-5 调节秀丽隐杆线虫减数分裂耐热性

 抽象的

减数分裂产生所有有性生殖生物体所需的单倍体配子，发生在不同生物体的特定温度范围内。然而，减数分裂耐热性是如何调节的仍然很大程度上未知。使用模型生物秀丽隐杆线虫，我们确定了联会复合体（SC）蛋白 SYP-5 作为减数分裂耐热性的关键调节因子。 syp-5缺失突变体在20°C下维持了高比例的可存活后代，但在25°C（野生型蠕虫允许的温度）下产生的可存活后代明显较少。对突变体减数分裂事件的细胞学分析表明，虽然 SC 组装和分解以及 DNA 双链断裂修复动力学不受高温影响，但交换指定和二价形成受到显着影响。在升高的温度下还观察到更严重的同系物分离错误。温度转换测定表明，减数分裂前期事件对温度不敏感，粗线期期间的减数分裂缺陷是导致syp-5突变体在高温下活力降低的原因。此外，SC多复合物的形成和己二醇敏感性分析表明，SYP-5是SC正常特性所必需的，并且SC组分中的电荷相互作用元件参与调节减数分裂耐热性。总之，这些发现为减数分裂耐热性调节提供了一种新的分子机制。