Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA.
Mol Microbiol. 2011 Jan;79(1):180-91. doi: 10.1111/j.1365-2958.2010.07440.x. Epub 2010 Nov 2.
Brh2, a member of the BRCA2 family of proteins, governs homologous recombination in the fungus Ustilago maydis through interaction with Rad51. Brh2 serves at an early step in homologous recombination to mediate Rad51 nucleoprotein filament formation and also has the capability to function at a later step in recombination through its inherent DNA annealing activity. Rec2, a Rad51 paralogue, and Rad52 are additional components of the homologous recombination system, but the absence of either is less critical than Brh2 for operational activity. Here we tested a variety of mutant forms of Brh2 for activity in recombinational repair as measured by DNA repair proficiency. We found that a mutant of Brh2 deleted of the non-canonical DNA-binding domain within the N-terminal region is dependent upon the presence of Rad52 for DNA repair activity. We also determined that a motif first identified in human BRCA2 as important in binding DMC1 also contributes to DNA repair proficiency and cooperates with the BRC element in Rad51 binding.
Brh2 是 BRCA2 家族蛋白的成员，通过与 Rad51 的相互作用来调控真菌 Ustilago maydis 中的同源重组。Brh2 在同源重组的早期步骤中发挥作用，介导 Rad51 核蛋白丝的形成，并且还具有通过其固有的 DNA 退火活性在重组的后期步骤中发挥作用的能力。Rec2 是 Rad51 的同源物，Rad52 是同源重组系统的其他组成部分，但缺失任何一个对于功能活性都不如 Brh2 关键。在这里，我们测试了 Brh2 的各种突变形式在 DNA 修复效率测量的重组修复中的活性。我们发现，缺失 N 端区域中非典型 DNA 结合域的 Brh2 突变体依赖于 Rad52 来进行 DNA 修复活性。我们还确定了在人类 BRCA2 中首次被确定为与 DMC1 结合重要的基序也有助于 DNA 修复效率，并与 Rad51 结合的 BRC 元件合作。
