biostudies-literatureDrosopoulos WCNIGMS NIH HHS191-208https://www.ebi.ac.uk/biostudies/studies/S-EPMC4508891biostudies-literatureUnknown210(2)Based on its in vitro unwinding activity on G-quadruplex (G4) DNA, the Bloom syndrome-associated helicase BLM is proposed to participate in telomere replication by aiding fork progression through G-rich telomeric DNA. Single molecule analysis of replicated DNA (SMARD) was used to determine the contribution of BLM helicase to telomere replication. In BLM-deficient cells, replication forks initiating from origins within the telomere, which copy the G-rich strand by leading strand synthesis, moved slower through the telomere compared with the adjacent subtelomere. Fork progression through the telomere was further slowed in the presence of a G4 stabilizer. Using a G4-specific antibody, we found that deficiency of BLM, or another G4-unwinding helicase, the Werner syndrome-associated helicase WRThe Journal of cell biologyBLM helicase facilitates telomere replication during leading strand synthesis of telomeres.PMC4508891R01 GM0457515R01-GM045751Drosopoulos WCKosiyatrakul STSchildkraut CLfalseBLM helicase facilitates telomere replication during leading strand synthesis of telomeres.Based on its in vitro unwinding activity on G-quadruplex (G4) DNA, the Bloom syndrome-associated helicase BLM is proposed to participate in telomere replication by aiding fork progression through G-rich telomeric DNA. Single molecule analysis of replicated DNA (SMARD) was used to determine the contribution of BLM helicase to telomere replication. In BLM-deficient cells, replication forks initiating from origins within the telomere, which copy the G-rich strand by leading strand synthesis, moved slower through the telomere compared with the adjacent subtelomere. Fork progression through the telomere was further slowed in the presence of a G4 stabilizer. Using a G4-specific antibody, we found that deficiency of BLM, or another G4-unwinding helicase, the Werner syndrome-associated helicase WR2015-01-01T00:00:00Z2015 Jul2025-04-26T08:15:06.109Z2019-03-27T01:55:30ZS-EPMC45088912619566410.1083/jcb.201410061