Duplication of a truncated paralog of the family B DNA polymerase gene Aa-polB in the Agrocybe aegerita mitochondrial genome.
The Agrocybe aegerita mitochondrial genome contains a truncated family B DNA polymerase gene (Aa-polB P1) whose nucleotide sequence is 86% identical to the previously described and potentially functional Aa-polB gene. A tRNA(Met) gene occurs at the 3' end of the Aa-polB P1 gene. The Aa-polB P1 gene could result from reverse transcription of an Aa-polB mRNA primed by a tRNA(Met) followed by the integration of the cDNA after recombination at the mitochondrial tRNA locus. Two naturally occurring alleles of Aa-polB P1 carry one or two copies of the disrupted sequence. In strains with two copies of Aa-polB P1, these copies are inverted relative to one another and separated by a short sequence carrying the tRNA(Met) gene. Both A. aegerita mitochondrial family B DNA polymerases were found to be related to other family B DNA polymerases (36 to 53% amino acid similarity), including the three enzymes of the archaebacterium Sulfolobus solfataricus. If mitochondria originated from a fusion between a Clostridium-like eubacterium and a Sulfolobus-like archaebacterium, then the A. aegerita family B DNA polymerase genes could be remnants of the archaebacterial genes.
Barroso
G
G
Laboratoire de Génétique Moléculaire et d'Amélioration des Champignons Cultivés, Université Victor Segalen Bordeaux 2-INRA, I.B.V.M., CRA de Bordeaux, 33883 Villenave d'Ornon Cédex, France.
Bois
F
F
Labarère
J
J
D000363:Agaricales / Q000235:genetics* / Q000254:growth & development; D000595:Amino Acid Sequence; D004271:DNA, Fungal / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D005656:Fungal Proteins; D020440:Gene Duplication; D016681:Genome, Fungal; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D005656:Fungal Proteins; C432943:PolB P1 protein, Agrocybe aegerita; C432942:PolB protein, Agrocybe aegerita; D004259:DNA-Directed DNA Polymerase