Yu David S, Sonoda Eiichiro, Takeda Shunichi, Huang Christopher L H, Pellegrini Luca, Blundell Tom L, Venkitaraman Ashok R
CR UK Department of Oncology and The Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 2XZ, United Kingdom.
Mol Cell. 2003 Oct;12(4):1029-41. doi: 10.1016/s1097-2765(03)00394-0.
Here, we visualize GFP-Rad51 fusion proteins in the nucleus of living cells to demonstrate the dynamic compartmentalization of Rad51 by self-association or by binding to BRCA2. Mutants of Rad51 that fail to oligomerize and/or to bind BRCA2 distinguish three fractions of Rad51 within the nucleoplasm: a relatively mobile fraction, an immobile oligomerized fraction, and an immobile BRCA2-bound fraction. Strikingly, inhibition of replication by hydroxyurea reduces the immobile fraction of nucleoplasmic Rad51. This effect is specific to Rad51 mutants that retain the capacity to bind BRCA2, indicating that the BRCA2-bound fraction is selectively mobilized. We propose that arrested replication triggers a switch between dual functions of BRCA2 in sequestering or mobilizing a small fraction of nucleoplasmic Rad51 and suggest a mechanism for the dynamic control of protein complexes that participate in homologous recombination.
在这里，我们对活细胞细胞核中的绿色荧光蛋白（GFP）-Rad51融合蛋白进行可视化，以证明Rad51通过自缔合或与BRCA2结合实现动态区室化。无法寡聚化和/或结合BRCA2的Rad51突变体可区分核质中Rad51的三个部分：相对可移动部分、不可移动的寡聚化部分和不可移动的BRCA2结合部分。引人注目的是，羟基脲抑制复制会减少核质Rad51的不可移动部分。这种效应对于保留结合BRCA2能力的Rad51突变体具有特异性，表明BRCA2结合部分被选择性地动员。我们提出，停滞的复制会触发BRCA2在隔离或动员一小部分核质Rad51方面的双重功能之间的转换，并提出了一种参与同源重组的蛋白质复合物动态控制机制。
