Competing crossover pathways act during meiosis in Saccharomyces cerevisiae
Competing crossover pathways act during meiosis in Saccharomyces cerevisiae
复制标题
DOI：
10.1534/genetics.104.032912
复制
发表时间：
2004-12-01
期刊：
影响因子：
3.3
通讯作者：
Alani, E
中科院分区：
文献类型：
--
作者：
Argueso, JL;Wanat, J;Alani, E
在酿酒酵母中，MSH 4-MSH 5、MLH 1-MLH 3和MUS 81-MMS 4复合物在减数分裂期间起促进交换的作用。MSH 4-MSH 5，而不是MUS 81-MMS 4，促进显示干扰的交叉。MLH 1-MLH 3在交叉控制中的作用不太清楚，部分原因是mlh 1Delta突变体保留了交叉干扰，但显示出交叉减少，其严重程度仅略低于msh 4Delta和msh 5Delta突变体。我们使用新开发的计算机软件分析了msh 5Delta，mlh 1Delta和mms 4Delta单，双和三重突变体在染色体XV上连续四个遗传间隔的减数分裂交叉的影响。mlh 1 Δ mms 4 Δ双突变体在所有突变体组合中显示出最大的交叉减少（13- 15倍），但这些菌株显示出相对高的孢子活力（42%）。相比之下，msh 5Delta mms 4Delta和msh 5Delta mms 4Delta mlh 1Delta突变体在交换中显示出较小的降低（4- 6倍）;然而，这些菌株的孢子活力（18-19%）低于mlh 1Delta mms 4Delta菌株。这些数据表明，减数分裂交换可以发生在酵母通过三个不同的交换途径。在一个途径中，MUS 81-MMS 4促进干扰非依赖性交换;在第二个途径中，MSH 4-MSH 5和MLH 1-MLH 3都促进干扰依赖性交换。第三种途径似乎被MSH 4-MSH 5抑制，产生有害的交叉。
In Saccharomyces cerevisiae the MSH4-MSH5, MLH1-MLH3, and MUS81-MMS4 complexes act to promote crossing over during meiosis. MSH4-MSH5, but not MUS81-MMS4, promotes crossovers that display interference. A role for MLH1-MLH3 in crossover control is less clear partly because mlh1Delta mutants retain crossover interference yet display a decrease in crossing over that is only slightly less severe than that seen in msh4Delta and msh5Delta mutants. We analyzed the effects of msh5Delta, mlh1Delta, and mms4Delta single, double, and triple mutants on meiotic crossing over at four consecutive genetic intervals on chromosome XV using newly developed computer software. mlh1Delta mms4Delta double mutants displayed the largest decrease in crossing over (13- to 15-fold) of all mutant combinations, yet these strains displayed relatively high spore viability (42%). In contrast, msh5Delta mms4Delta and msh5Delta mms4Delta mlh1Delta mutants displayed smaller decreases in crossing over (4- to 6-fold); however, spore viability (18-19%) was lower in these strains than in mlh1Delta mms4Delta strains. These data suggest that meiotic crossing over can occur in yeast through three distinct crossover pathways. In one pathway MUS81-MMS4 promotes interference-independent crossing over; in a second pathway, both MSH4-MSH5 and MLH1-MLH3 promote interference-dependent crossovers. A third pathway, which appears to be repressed by MSH4-MSH5, yields deleterious crossovers.