title: Analysis of replication intermediates indicates that Drosophila melanogaster mitochondrial DNA replicates by a strand-coupled theta mechanism.
abstract: Mitochondrial DNA synthesis is necessary for the normal function of the organelle and for the eukaryotic organism as a whole. Here we demonstrate, using two-dimensional agarose gel electrophoresis to analyse replication intermediates, that unidirectional, strand-coupled DNA synthesis is the prevalent mode of mtDNA replication in Drosophila melanogaster. Commencing within the single, extended non-coding region (NCR), replication proceeds around the circular genome, manifesting an irregular rate of elongation, and pausing frequently in specific regions. Evidence for a limited contribution of strand-asynchronous DNA synthesis was found in a subset of mtDNA molecules, but confined to the ribosomal RNA gene region, just downstream of the NCR. Our findings imply that strand-coupled replication is widespread amongst metazoans, and should inform future research on mtDNA metabolism in D. melanogaster.
authors: Institute of Biomedical Technology and Tampere University Hospital, University of Tampere, Tampere, Finland.
authors: Priit
authors: P
authors: Jõers
authors: Howard T
authors: HT
authors: Jacobs
mesh_terms: D000818:Animals; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D004331:Drosophila melanogaster / Q000737:chemistry / Q000235:genetics*; D015180:Electrophoresis, Gel, Two-Dimensional; D056426:Genetic Loci; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal