Allers T, Lichten M
Laboratory of Biochemistry, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
Mol Cell. 2001 Jul;8(1):225-31. doi: 10.1016/s1097-2765(01)00280-5.
The formation of heteroduplex DNA features prominently in all models for homologous recombination. A central intermediate in the current double-strand break repair model contains two Holliday junctions flanking a region of heteroduplex DNA. Studies of yeast meiosis have identified such intermediates but failed to detect associated heteroduplex DNA. We show here that these intermediates contain heteroduplex DNA, providing an important validation of the double-strand break repair model. However, we also detect intermediates where both Holliday junctions are to one side of the initiating DSB site, while the intervening region shows no evidence of heteroduplex DNA. Such structures are not easily accommodated by the canonical version of the double-strand break repair model.
异源双链DNA的形成在所有同源重组模型中都占据显著地位。当前双链断裂修复模型中的一个核心中间体包含两个位于异源双链DNA区域两侧的霍利迪连接体。对酵母减数分裂的研究已鉴定出此类中间体，但未能检测到相关的异源双链DNA。我们在此表明，这些中间体含有异源双链DNA，为双链断裂修复模型提供了重要验证。然而，我们也检测到了这样的中间体，即两个霍利迪连接体都位于起始双链断裂位点的一侧，而中间区域没有异源双链DNA的迹象。双链断裂修复模型的经典版本难以解释此类结构。
