ATP-dependent DNA helicase implicated in telomere-length regulation, DNA repair and the maintenance of genomic stability. Acts as an anti-recombinase to counteract toxic recombination and limit crossover during meiosis. Regulates meiotic recombination and crossover homeostasis by physically dissociating strand invasion events and thereby promotes noncrossover repair by meiotic synthesis dependent strand annealing (SDSA) as well as disassembly of D loop recombination intermediates. Also disassembles T loops and prevents telomere fragility by counteracting telomeric G4-DNA structures, which together ensure the dynamics and stability of the telomere. ATP + H2O = ADP + H(+) + phosphate Interacts with TERF1. Interacts (via PIP-box) with PCNA; the interaction is direct and essential for suppressing telomere fragility. Interacts with MMS19; the interaction mediates the association of RTEL1 with the cytosolic iron-sulfur protein assembly (CIA) complex. Colocalizes with PCNA within the replication foci in S-phase cells. The PIP-box (PCNA interacting peptide) motif mediates the interaction with PCNA and localization to replication foci. Belongs to the helicase family. RAD3/XPD subfamily.