Ewing Tumor-Associated Antigen 1 Interacts with Replication Protein A to Promote Restart of Stalled Replication Forks.

Abstract The replication protein A (RPA) complex binds single-stranded DNA generated at stalled replication forks and recruits other DNA repair proteins to promote recovery of these forks. Here we identify Ewing Tumor-Associated Antigen 1 (ETAA1), which has been linked to susceptibility to pancreatic cancer, as a new repair protein that is recruited to stalled forks by RPA. We demonstrate that ETAA1 interacts with RPA through two regions, each of which resembles to previously identified RPA-binding domains: RPA70N-binding motif and RPA32C-binding motif, respectively. In response to replication stress, ETAA1 is recruited to stalled forks where it colocalizes with RPA; and this recruitment is diminished when RPA is depleted. Notably, inactivation of ETAA1 gene increases the collapse level of the stalled replication forks and decreased the recovery efficiency of these forks. Moreover, epistasis analysis shows that ETAA1 stabilizes stalled replication forks in an ATR-independent manner. Thus, our results reveal that ETAA1 is a novel RPA-interacting protein that promotes restart of stalled replication forks.