Klein S, Zenvirth D, Sherman A, Ried K, Rappold G, Simchen G
Department of Genetics, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
Nat Genet. 1996 Aug;13(4):481-4. doi: 10.1038/ng0896-481.
Meiotic recombination in the yeast Saccharomyces cerevisiae is initiated at double-strand breaks (DSBs), which occur preferentially at specific locations. Genetically mapped regions of elevated meiotic recombination ('hotspots') coincide with meiotic DSB sites, which can be identified on chromosome blots of meiotic DNA (refs 4,5; S.K. et al., manuscript submitted). The morphology of yeast artificial chromosomes (YACs) containing human DNA during the pachytene stage of meiosis resembles that of native yeast chromosomes. Homologous YAC pairs segregate faithfully and recombine at the high rates characteristic of S. cerevisiae (vs. approximately 0.4 cM/kb in S. cerevisiae versus approximately 10-3 cM/kb in humans). We have examined a variety of YACs carrying human DNA inserts for double-strand breakage during yeast meiosis. Each YAC has a characteristic set of meiotic DSB sites, as do yeast chromosomes (S.K. et al., manuscript submitted). We show that the positions of the DSB sites in the YACs depend on the human-derived DNA in the clones. The degree of double-strand breakage in yeast meiosis of the YACs in our study appears to reflect the degree of meiotic recombination in humans.
酿酒酵母中的减数分裂重组起始于双链断裂（DSB），这些双链断裂优先发生在特定位置。减数分裂重组增强的基因定位区域（“热点”）与减数分裂DSB位点重合，减数分裂DSB位点可在减数分裂DNA的染色体印迹上识别（参考文献4、5；S.K.等人，稿件待提交）。在减数分裂粗线期，含有人类DNA的酵母人工染色体（YAC）的形态与天然酵母染色体相似。同源YAC对能够忠实分离，并以酿酒酵母特有的高频率进行重组（酿酒酵母中约为0.4 cM/kb，而人类中约为10 - 3 cM/kb）。我们检测了多种携带人类DNA插入片段的YAC在酵母减数分裂过程中的双链断裂情况。每个YAC都有一组特定的减数分裂DSB位点，酵母染色体也是如此（S.K.等人，稿件待提交）。我们发现，YAC中DSB位点的位置取决于克隆中人类来源的DNA。在我们的研究中，YAC在酵母减数分裂中的双链断裂程度似乎反映了人类减数分裂重组的程度。
