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. Widely expressed. Expressed in spleen, thymus, Peyer patches, kidney, and intestine. Not expressed in brain, heart, lung, skeletal muscles, skin and white fat. In the adult gonad, it is highly expressed in the testis, mainly in the spermatogonia and meiotic spermatocytes. Widely expressed in 8.5 dpc and 9.5 dpc embryos with a more restricted expression pattern at 13.5 dpc-15.5 dpc. In general, expression in embryos coincides with areas of actively proliferating cells. The PIP-box (PCNA interacting peptide) motif mediates the interaction with PCNA and localization to replication foci. Death between days 10 and 11.5 of gestation with defects in the nervous system, heart, vasculature and extraembryonic tissues. Effects are due to severe genome instability and stochastic telomere loss in embryonic stem cells which display many chromosome breaks and fusions upon differentiation in vitro. Able to elongate M.spretus telomeres in crosses between M.musculus and M.spretus. Belongs to the helicase family. RAD3/XPD subfamily. Extended N-terminus.