The yeast MER2 gene is required for chromosome synapsis and the initiation of meiotic recombination.
The yeast MER2 gene is required for chromosome synapsis and the initiation of meiotic recombination.
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发表时间：
1995-09
期刊：
影响因子：
3.3
通讯作者：
B. Rockmill;J. Engebrecht;H. Scherthan;J. Loidl;G. Roeder
中科院分区：
文献类型：
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作者：
B. Rockmill;J. Engebrecht;H. Scherthan;J. Loidl;G. Roeder
酿酒酵母MER2基因的突变赋予减数分裂致死性。为了深入了解Mer2蛋白的功能，我们对Mer2无效突变体进行了详细的表征。遗传分析表明，mer2完全消除了减数分裂染色体间的基因转换和交换。此外，mer2废除染色体内减数分裂重组，无论是在核糖体DNA阵列和人工复制。物理测定的结果表明，Mer2突变防止减数分裂特异性双链断裂的形成，表明Mer2蛋白在减数分裂重组开始时或之前起作用。电子显微镜分析显示，mer2突变体使轴向元素，这是联会复合体的前体，但同源染色体不能联会。染色体特异性DNA探针的荧光原位杂交，以传播减数分裂染色体表明，同源物对齐也显着减少在mer2突变体。尽管MER 2基因在营养生长过程中转录，但MER 2基因的缺失或过表达对有丝分裂重组或DNA损伤修复没有明显影响。我们认为mer2突变体的主要缺陷在于减数分裂遗传交换的启动。
Mutation of the MER2 gene of Saccharomyces cerevisiae confers meiotic lethality. To gain insight into the function of the Mer2 protein, we have carried out a detailed characterization of the mer2 null mutant. Genetic analysis indicates that mer2 completely eliminates meiotic interchromosomal gene conversion and crossing over. In addition, mer2 abolishes intrachromosomal meiotic recombination, both in the ribosomal DNA array and in an artificial duplication. The results of a physical assay demonstrate that the mer2 mutation prevents the formation of meiosis-specific, double-strand breaks, indicating that the Mer2 protein acts at or before the initiation of meiotic recombination. Electron microscopic analysis reveals that the mer2 mutant makes axial elements, which are precursors to the synaptonemal complex, but homologous chromosomes fail to synapse. Fluorescence in situ hybridization of chromosome-specific DNA probes to spread meiotic chromosomes demonstrates that homolog alignment is also significantly reduced in the mer2 mutant. Although the MER2 gene is transcribed during vegetative growth, deletion or overexpression of the MER2 gene has no apparent effect on mitotic recombination or DNA damage repair. We suggest that the primary defect in the mer2 mutant is in the initiation of meiotic genetic exchange.