Updated project metadata.
Replication fork reversal is a key protective mechanism against replication stress in higher eukaryotic cells and occurs via a series of coordinated enzymatic reactions. The Bloom syndrome gene product, BLM, is a member of the highly conserved RecQ helicase family and has been implicated in this process, but its precise regulation and role remain poorly understood. Here, we show that, upon replication stress, the GCFC domain-containing protein TFIP11 competes with the BLM helicase for association with stalled replication forks, thereby facilitates RAD51-mediated stalled fork reversal. Consequently, loss of TFIP11 results in aberrant accumulation of BLM at stalled forks, which in turn compromises RAD51 recruitment, impairs replication stress-induced fork reversal and slowing, hypersensitizes cells to replication stress-inducing agents, and enhances chromosomal instability. These findings reveal a previously unidentified regulatory mechanism that modulates the activities of BLM and RAD51 at stalled forks and thus genome integrity.