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 ?. 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.

SUBMITTER: Jemt E 

PROVIDER: S-EPMC3241658 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature