Functional analysis of the FANCD2 interactors containing ubiquitin binding domain

范可尼贫血（FA）通路在DNA损伤反应和DNA修复中起关键作用。一个关键的蛋白质，FANCD 2，是monoubiquitinated和积累在染色质中响应DNA链间交联（ICLs），在那里它协调DNA修复通过机制，仍然知之甚少。这两种蛋白质都含有泛素结合域。我们已经建立了ubr 5缺陷的鸡DT 40细胞和基于siRNA的ufd 1敲低的人细胞。出乎意料的是，与野生型细胞相比，ubr 5缺陷型或ufd 1敲低细胞对ICL试剂显示出很小的敏感性。使用表达GFP-UBR 5或GFP-UFD 1的人细胞的激光微照射实验显示，DNA损伤后GFP蛋白的积累很少。这些结果表明FA途径与UBR 5或UFD 1（包括相关蛋白）之间的功能关系并不强，至少在ICL修复中是这样。

The Fanconi anemia (FA) pathway is critically involved in DNA damage responses and DNA repair. A key protein, FANCD2, is monoubiquitinated and accumulates in chromatin in response to DNA interstrand crosslinks (ICLs), where it coordinates DNA repair through mechanisms that are still poorly understand.We have isolated UBR5 and UFD1 as candidate interacting proteins for FANCD2. Both proteins contain ubiquitin-binding domains. We have established ubr5-deficient chicken DT40 cells, and SiRNA-based ufd1-knock down human cells. Unexpectedly, ubr5-deficient or ufd1-knock down cells showed little sensitivity to ICL reagents compared to wild type cells. Laser microirradiation experiments using GFP-UBR5 or GFP-UFD1 expressing human cells showed little GFP-protein accumulation after DNA damage. These results suggested that functional relationship between FA pathway and UBR5, or UFD1 including related proteins was not strong, at least in ICL repair.