title: RECQ1 interacts with FEN-1 and promotes binding of FEN-1 to telomeric chromatin.
abstract: RecQ helicases are a family of highly conserved proteins that maintain genomic stability through their important roles in replication restart mechanisms. Cellular phenotypes of RECQ1 deficiency are indicative of aberrant repair of stalled replication forks, but the molecular functions of RECQ1, the most abundant of the five known human RecQ homologues, have remained poorly understood. We show that RECQ1 associates with FEN-1 (flap endonuclease-1) in nuclear extracts and exhibits direct protein interaction in vitro. Recombinant RECQ1 significantly stimulated FEN-1 endonucleolytic cleavage of 5'-flap DNA substrates containing non-telomeric or telomeric repeat sequence. RECQ1 and FEN-1 were constitutively present at telomeres and their binding to the telomeric chromatin was enhanced following DNA damage. Telomere residence of FEN-1 was dependent on RECQ1 since depletion of RECQ1 reduced FEN-1 binding to telomeres in unperturbed cycling cells. Our results confirm a conserved collaboration of human RecQ helicases with FEN-1 and suggest both overlapping and specialized roles of RECQ1 in the processing of DNA structure intermediates proposed to arise during replication, repair and recombination.
authors.affiliation: *Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street NW, Washington, DC 20059, U.S.A.
authors.forename: Furqan
authors.initials: F
authors.lastname: Sami
authors.affiliation: *Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street NW, Washington, DC 20059, U.S.A.
authors.forename: Xing
authors.initials: X
authors.lastname: Lu
authors.affiliation: *Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street NW, Washington, DC 20059, U.S.A.
authors.forename: Swetha
authors.initials: S
authors.lastname: Parvathaneni
authors.affiliation: †Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, 3800 Reservoir Road NW, Washington, DC 20057, U.S.A.
authors.forename: Rabindra
authors.initials: R
authors.lastname: Roy
authors.affiliation: ‡Department of Chemistry, University of Nevada, Las Vegas 4505 Maryland Parkway, Las Vegas, NV 89154-4003, U.S.A.
authors.forename: Ronald K
authors.initials: RK
authors.lastname: Gary
authors.affiliation: *Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street NW, Washington, DC 20059, U.S.A.
authors.forename: Sudha
authors.initials: S
authors.lastname: Sharma
mesh_terms: D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D004249:DNA Damage; D004261:DNA Replication; D045585:Flap Endonucleases / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D045585:Flap Endonucleases; C468317:FEN1 protein, human; C506725:RECQL protein, human; D053484:RecQ Helicases