The single-end invasion: An asymmetric intermediate at the double-strand break to double-holliday junction transition of meiotic recombination
The single-end invasion: An asymmetric intermediate at the double-strand break to double-holliday junction transition of meiotic recombination
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DOI：
10.1016/s0092-8674(01)00430-5
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发表时间：
2001-07-13
期刊：
影响因子：
64.5
通讯作者：
Kleckner, N
中科院分区：
文献类型：
--
作者：
Hunter, N;Kleckner, N
我们确定了一种新的减数分裂重组中间体，单端入侵（SEI），这发生在双链断裂（DSB）的双霍利迪连接（dHJ）的过渡。SEI是一个DSB末端与其同源物之间的链交换的产物。SEIs的结构不对称性表明DSB的两端通过结构上（因此生物化学上）不同的过程与同系物在时间上连续相互作用。SEI出现令人惊讶的后期前期，伴随着联会复合体（SC）的形成。这些和其他数据意味着，SEI之前的新生DSB合作伙伴中间体，然后进行选择性分化为交叉和noncrossover类型，与SC的形成和链交换作为下游的后果。链交换的晚发生提供了逆转重组命运的机会，甚至在同源物共对齐和/或突触后。这一特征可以解释同源异型和结构杂合染色体之间的交叉抑制。
We identify a novel meiotic recombination intermediate, the single-end invasion (SEI), which occurs during the transition from double-strand breaks (DSBs) to double-Holliday junction (dHJs). SEIs are products of strand exchange between one DSB end and its homolog. The structural asymmetry of SEIs indicates that the two ends of a DSB interact with the homolog in temporal succession, via structurally (and thus biochemically) distinct processes. SEIs arise surprisingly late in prophase, concomitant with synaptonemal complex (SC) formation. These and other data imply that SEIs are preceded by nascent DSB-partner intermediates, which then undergo selective differentiation into crossover and noncrossover types, with SC formation and strand exchange as downstream consequences. Late occurrence of strand exchange provides opportunity to reverse recombinational fate even after homologs are coaligned and/or synapsed. This feature can explain crossover suppression between homeologous and structurally heterozygous chromosomes.