Rad54蛋白通过Rad51核蛋白丝被靶向至配对位点。

Rad54 protein is targeted to pairing loci by the Rad51 nucleoprotein filament.

作者信息

Mazin A V, Bornarth C J, Solinger J A, Heyer W D, Kowalczykowski S C

机构信息

Division of Biological Sciences, University of California, Davis 95616, USA.

出版信息

Mol Cell. 2000 Sep;6(3):583-92. doi: 10.1016/s1097-2765(00)00057-5.

DOI:10.1016/s1097-2765(00)00057-5

PMID:11030338

Abstract

Rad51 and Rad54 proteins are important for the repair of double-stranded DNA (dsDNA) breaks by homologous recombination in eukaryotes. Rad51 assembles on single-stranded DNA (ssDNA) to form a helical nucleoprotein filament that performs homologous pairing with dsDNA; Rad54 stimulates this pairing substantially. Here, we demonstrate that Rad54 acts in concert with the mature Rad51-ssDNA filament. Enhancement of DNA pairing by Rad54 is greatest at an equimolar ratio relative to Rad51 within the filament. Reciprocally, the Rad51-ssDNA filament enhances both the dsDNA-dependent ATPase and the dsDNA unwinding activities of Rad54. We conclude that Rad54 participates in the DNA homology search as a component of the Rad51-nucleoprotein filament and that the filament delivers Rad54 to the dsDNA pairing locus, thereby linking the unwinding of potential target DNA with the homology search process.

摘要

Rad51和Rad54蛋白对于真核生物中通过同源重组修复双链DNA（dsDNA）断裂至关重要。Rad51组装在单链DNA（ssDNA）上形成螺旋核蛋白丝，该丝与dsDNA进行同源配对；Rad54能显著刺激这种配对。在此，我们证明Rad54与成熟的Rad51-ssDNA丝协同作用。相对于丝中的Rad51，Rad54在等摩尔比时对DNA配对的增强作用最大。相反，Rad51-ssDNA丝增强了Rad54的dsDNA依赖性ATP酶活性和dsDNA解旋活性。我们得出结论，Rad54作为Rad51-核蛋白丝的一个组成部分参与DNA同源性搜索，并且该丝将Rad54传递到dsDNA配对位点，从而将潜在靶DNA的解旋与同源性搜索过程联系起来。