title: The mitochondrial DNA helicase TWINKLE can assemble on a closed circular template and support initiation of DNA synthesis.
abstract: Mitochondrial DNA replication is performed by a simple machinery, containing the TWINKLE DNA helicase, a single-stranded DNA-binding protein, and the mitochondrial DNA polymerase γ. In addition, mitochondrial RNA polymerase is required for primer formation at the origins of DNA replication. TWINKLE adopts a hexameric ring-shaped structure that must load on the closed circular mtDNA genome. In other systems, a specialized helicase loader often facilitates helicase loading. We here demonstrate that TWINKLE can function without a specialized loader. We also show that the mitochondrial replication machinery can assemble on a closed circular DNA template and efficiently elongate a DNA primer in a manner that closely resembles initiation of mtDNA synthesis in vivo.
authors.affiliation: Department of Medical Biochemistry and Cell Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Jemt
authors.forename: Géraldine
authors.initials: G
authors.lastname: Farge
authors.forename: Stefan
authors.initials: S
authors.lastname: Bäckström
authors.forename: Teresa
authors.initials: T
authors.lastname: Holmlund
authors.forename: Claes M
authors.initials: CM
authors.lastname: Gustafsson
authors.forename: Maria
authors.initials: M
authors.lastname: Falkenberg
mesh_terms: D004247:DNA / Q000096:biosynthesis*; D004265:DNA Helicases / Q000378:metabolism*; D000074002:DNA Polymerase gamma; D004261:DNA Replication; D004270:DNA, Circular / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D013696:Temperature; D013698:Templates, Genetic
chemical_list: D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; D009711:Nucleotides; D004247:DNA; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; D004265:DNA Helicases