A model of one of the pathways of replication fork recovery from HU-induced arrest. An arrested fork regresses, forming a daughter/daughter strand duplex. This duplex is resected and/or unwound to expose a 3′ single-stranded tail. WRN and BLM can perform unwinding or assist resection. The tail invades the parental duplex in a RAD51-dependent manner, forming a D-loop. Extension of a D-loop may be stimulated by WRN. Note that if resection/unwinding of the daughter/daughter duplex is incomplete, remaining linkage of paired strands can persist after the D-loop is converted into a reactivated fork, and even after S phase is completed. At mitosis, this hemicatenation between sister chromatids can be dissolved by BLM (in complex with topoIIIα and RMIs).