Fanconi-Anemia-Associated Mutations Destabilize RAD51 Filaments and Impair Replication Fork Protection

• Published in: Cell reports (Cambridge) Vol. 21; no. 2; pp. 333 - 340
• Main Authors: Zadorozhny, Karina, Sannino, Vincenzo, Beláň, Ondrej, Mlčoušková, Jarmila, Špírek, Mário, Costanzo, Vincenzo, Krejčí, Lumír
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10.10.2017; Elsevier
• Subjects: Adenosine Triphosphate - metabolism; Animals; DNA Replication; Fanconi anemia; Fanconi Anemia - genetics; Humans; MRE11 Homologue Protein - metabolism; Mutation; Protein Binding; Protein Stability; RAD51; Rad51 Recombinase - genetics; Rad51 Recombinase - metabolism; recombination; replication; Xenopus; replication; RAD51; recombination; Fanconi anemia
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2017.09.062

Fanconi anemia (FA) is a genetic disorder characterized by a defect in DNA interstrand crosslink (ICL) repair, chromosomal instability, and a predisposition to cancer. Recently, two RAD51 mutations were reported to cause an FA-like phenotype. Despite the tight association of FA/HR proteins with replication fork (RF) stabilization during normal replication, it remains unknown how FA-associated RAD51 mutations affect replication beyond ICL lesions. Here, we report that these mutations fail to protect nascent DNA from MRE11-mediated degradation during RF stalling in Xenopus laevis egg extracts. Reconstitution of DNA protection in vitro revealed that the defect arises directly due to altered RAD51 properties. Both mutations induce pronounced structural changes and RAD51 filament destabilization that is not rescued by prevention of ATP hydrolysis due to aberrant ATP binding. Our results further interconnect the FA pathway with DNA replication and provide mechanistic insight into the role of RAD51 in recombination-independent mechanisms of genome maintenance. [Display omitted] •FA-associated RAD51 mutants are defective at stalled fork protection•Structural properties of the RAD51 nucleoprotein filament are altered by FA mutations•These filaments are highly unstable due to aberrant ATP binding and hydrolysis Zadorozhny et al. find that RAD51 mutations associated with Fanconi anemia not only impair DNA crosslink repair but also affect DNA replication during fork stalling. The mutant proteins cause RAD51 filament destabilization and induce pronounced structural changes resulting from aberrant ATP binding and hydrolysis.