Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom.
J Biol Chem. 2010 Apr 9;285(15):11427-32. doi: 10.1074/jbc.M110.108399. Epub 2010 Feb 22.
Eukaryotic Holliday junction (HJ) resolvases have attracted much attention recently with the identification of at least three distinct proteins that can cleave model HJs in vitro. However, the specific DNA structure(s) that these proteins act upon in the cell is unknown. Here, we describe a system in budding yeast to directly and quantitatively monitor in vivo HJ resolution. We found that Yen1 acts redundantly with Mus81, but not Slx1, to resolve a model HJ in vivo. This functional overlap specifically extends to the repair/bypass of lesions that impede the progression of replication forks but not to the repair of double-strand breaks induced by ionizing radiation. Together, these results suggest a direct role for Yen1 in the response to DNA damage and implicate overlapping HJ resolution functions of Yen1 with Mus81 during replication fork repair.
真核体 Holliday 连接（HJ）解旋酶最近引起了广泛关注，因为至少有三种不同的蛋白质可以在体外切割模型 HJ。然而，这些蛋白质在细胞中作用的确切 DNA 结构尚不清楚。在这里，我们描述了一种在芽殖酵母中直接和定量监测体内 HJ 解析的系统。我们发现 Yen1 与 Mus81 冗余地作用，但不与 Slx1 作用，以在体内解析模型 HJ。这种功能重叠特别扩展到修复/绕过阻碍复制叉前进的损伤，但不能修复电离辐射诱导的双链断裂。总之，这些结果表明 Yen1 在 DNA 损伤反应中具有直接作用，并暗示 Yen1 与 Mus81 在复制叉修复过程中具有重叠的 HJ 解析功能。
