加州大学Neil Hunter小组取得一项新突破。他们揭示了保护双假日连接点确保减数分裂期间的交叉。相关论文发表在2025年9月24日出版的《自然》杂志上。

在这里，该课题组展示了关键的SC组分通过依赖和相互依赖的关系发挥作用，以保护dHJ不被异常溶解为非交叉产物。条件消融实验表明，黏结蛋白是SC侧位元件的核心，在肿痛期维持突触和dHJ相关交叉重组复合物（CRCs）是必需的。SC中心区域的横向丝蛋白也是维持CRCs所必需的。反过来，SC中央区的稳定性要求CRCs的持续存在，有效地将突触与dHJ形成和突触断开耦合到分解。

然而，dHJ保护和CRC维持可以在没有SC中心区域的中心元件介导的端到端同源突触的情况下发生。课题组研究人员得出结论，SC组分的局部集合足以实现交叉特异性dHJ分辨率，以确保同源染色体的连接和分离。

据了解，在减数分裂过程中，通过交叉重组形成的染色体连锁对于同源染色体的准确分离至关重要。DNA重组事件与减数分裂染色体的结构成分有关。重要的是，双Holliday结（dHJ）中间体的偏解发生在突触复合体（SC）中，SC是减数分裂特异性结构，在长周期阶段介导同源物的端到端突触。然而，SC在交叉特异性dHJ解决中的作用尚不清楚。

附：英文原文

Title: Protecting double Holliday junctions ensures crossing over during meiosis

Author: Tang, Shangming, Hariri, Sara, Bohn, Regina, McCarthy, John E., Koo, Jennifer, Pourhosseinzadeh, Mohammad, Nguyen, Emerald, Liu, Natalie, Ma, Christopher, Lu, Hanyu, Lee, Monica, Hunter, Neil

Issue&Volume: 2025-09-24

Abstract: Chromosomal linkages formed through crossover recombination are essential for the accurate segregation of homologous chromosomes during meiosis1. The DNA events of recombination are linked to structural components of meiotic chromosomes2. Imperatively, the biased resolution of double Holliday junction (dHJ) intermediates into crossovers3,4 occurs within the synaptonemal complex (SC), the meiosis-specific structure that mediates end-to-end synapsis of homologues during the pachytene stage5,6. However, the role of the SC in crossover-specific dHJ resolution remains unclear. Here we show that key SC components function through dependent and interdependent relationships to protect dHJs from aberrant dissolution into non-crossover products. Conditional ablation experiments reveal that cohesin, the core of SC lateral elements, is required to maintain both synapsis and dHJ-associated crossover recombination complexes (CRCs) during pachytene. The SC central region transverse-filament protein is also required to maintain CRCs. Reciprocally, the stability of the SC central region requires the continuous presence of CRCs effectively coupling synapsis to dHJ formation and desynapsis to resolution. However, dHJ protection and CRC maintenance can occur without end-to-end homologue synapsis mediated by the central element of the SC central region. We conclude that local ensembles of SC components are sufficient to enable crossover-specific dHJ resolution to ensure the linkage and segregation of homologous chromosomes.

DOI: 10.1038/s41586-025-09555-1

Source: https://www.nature.com/articles/s41586-025-09555-1