Generating crossovers by resolution of nicked Holliday junctions: A role for Mus81-Eme1 in meiosis
Generating crossovers by resolution of nicked Holliday junctions: A role for Mus81-Eme1 in meiosis
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DOI：
10.1016/s1097-2765(03)00343-5
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发表时间：
2003-09-01
期刊：
影响因子：
16
通讯作者：
Whitby, MC
中科院分区：
文献类型：
--
作者：
Osman, F;Dixon, J;Whitby, MC
双霍利迪连接（dHJ）是减数分裂重组的关键中间体，其分离对形成交换重组体至关重要。在裂殖酵母中，Mus 81-Eme 1内切核酸酶与分解dHJ有关。与此作用相一致，我们表明，Mus 81-Eme 1是产生减数分裂交叉所必需的。然而，纯化的Mus 81-Eme 1倾向于切割模拟从双链断裂到dHJ过渡期间形成的连接。重要的是，这些连接被Mus 81-Eme 1以正确的方向切割，以确保每次形成交叉。这些数据表明，使用在真核生物中广泛保守的酶，在不形成或解析dHJ的情况下，如何产生交叉。
The double Holliday junction (dHJ) is generally regarded to be a key intermediate of meiotic recombination, whose resolution is critical for the formation of crossover recombinants. In fission yeast, the Mus81-Eme1 endonuclease has been implicated in resolving dHJs. Consistent with this role, we show that Mus81-Eme1 is required for generating meiotic crossovers. However, purified Mus81-Eme1 prefers to cleave junctions that mimic those formed during the transition from double-strand break to dHJ. Crucially, these junctions are cleaved by Mus81-Eme1 in precisely the right orientation to guarantee the formation of a crossover every time. These data demonstrate how crossovers could arise without forming or resolving dHJs using an enzyme that is widely conserved amongst eukaryotes.