title: A mitochondrial plasmid and plasmid-like RNA and DNA polymerases encoded within the mitochondrial genome of carrot (Daucus carota L.).
abstract: The mitochondrial genome of mitochondrial type (mitotype) SW3 of carrot (Daucus carota L.) encodes intact reading frames for a RNA polymerase (Rpo) and a DNA polymerase (Dpo) similar to those encoded by linear mitochondrial plasmids from plants. A BLAST search of translated nucleotide sequences in GenBank revealed previously unreported plasmid-like Rpo or Dpo sequence fragments in many plant mitochondrial DNAs. Phylogenetic analyses of the relationships between mitochondrial (mt)DNA-encoded and plasmid-encoded Rpos and Dpos from plants suggest that the mitochondrial sequences were derived from integrated plant plasmid sequences. A linear mitochondrial plasmid was detected in a different mitotype (FG21) of carrot by Southern hybridization of the Rpo and Dpo to undigested mtDNAs. Transcripts of the mtDNA-encoded Rpo and Dpo in mitotype SW3 were detected by RT-PCR.
authors.affiliation: Department of Plant Agriculture, University of Guelph, Bovey Building, Guelph, N1G 2W1, Ontario, Canada.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Robison
authors.forename: David J
authors.initials: DJ
authors.lastname: Wolyn
mesh_terms: D000595:Amino Acid Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000032:analysis / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000032:analysis / Q000235:genetics; D018552:Daucus carota / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial; D012321:DNA-Directed RNA Polymerases; D004259:DNA-Directed DNA Polymerase