Interference and NonInterference Recombination Pathways in Yeast

有证据支持酵母减数分裂重组的以下观点：双链断裂修复由两条途径控制，这两条途径由其修复中间产物的分解产物来区分。一种途径(类型I)产生从中间体的两个Holliday结的切割中预期的交叉和非交叉分辨率类型。另一种途径(类型II)只产生两种类型的交叉分辨率中的一种，这种交叉分辨率可能是通过在中间体中切割DNA链而产生的，以及一种似乎没有切割链的单一非交叉类型。II型中间体的交叉分辨取决于一组明显需要交叉干扰的蛋白质。I型中间体的交叉拆分独立于这些蛋白质发生，并且I型交叉显示很少或根本没有干扰。这些对酵母干扰的研究有望得出同样适用于哺乳动物和绿色植物的研究结果，有望为酵母与果蝇在交换方面的差异提供解释。通过这样做，他们将加强我们对减数分裂的理解，减数分裂是有性繁殖的基本特征。了解这一基本的生物过程将使生物学家能够为许多社会最紧迫的问题找到更好的解决方案

Evidence supports the following view of meiotic recombination in yeast: Double-strand-break repair is governed by two pathways, which are distinguished by the products of resolution of their repair intermediates. One pathway (Type I) yields the crossover and noncrossover resolution types expected from the cutting of both Holliday junctions of the intermediate. The other pathway (Type II) yields only one of the two types of crossover resolution that could arise from cutting DNA strands in the intermediate, along with a single noncrossover type that appears to arise without strand cutting. Crossover resolution of Type II intermediates depends on a set of proteins demonstrably required for crossover interference. Crossover resolution of Type I intermediates occurs independently of these proteins, and Type I crossovers display little or no interference. These studies of interference in yeast, which are expected to yield findings applicable to mammals and green plants as well, promise to provide an explanation for documented differences in crossing-over in yeast as compared with Drosophila. In so doing, they will enhance our understanding of meiosis, an essential feature of sexual reproduction. Understanding this basic biological process will enable biologists to develop better solutions to many of society's most pressing problems