Linear DNA plasmid pPK2 of Pichia kluyveri: distinction between cytoplasmic and mitochondrial linear plasmids in yeasts.
The linear plasmids frequently found in plants and filamentous fungi are associated with mitochondria or chloroplasts. In contrast, all the linear plasmids known in yeasts are cytoplasmic elements. From a strain of the yeast Pichia kluyveri, we have isolated a new linear plasmid, pPK2, which was found to be associated with mitochondria. This 7.1 kilobase pairs-long DNA contained only two genes, which code for DNA and RNA polymerases, as judged from their nucleotide sequences translated by a mitochondrial genetic code. When we examined several recently isolated yeast plasmids for their subcellular localization, we found that two linear plasmids, pPH1 from Pichia heedii, as well as pPK1 from another strain of P. kluyveri, were also localized in mitochondria. These plasmids are the first examples of mitochondria-associated linear plasmids in yeast. All other linear plasmids we examined were of cytoplasmic origin. Whilst the cytoplasmic type linear plasmids were efficiently eliminated by ultraviolet irradiation of host cells, the mitochondria-associated plasmids were highly resistant. The mitochondrial pPK2 plasmid was rapidly lost by treatment of the host cells with ethidum bromide.
Institut Curie, Section de Recherche, Centre Universitaire Paris XI, Bâtiment 110, Orsay 91405, France.
J
J
Blaisonneau
J
J
Nosek
H
H
Fukuhara
D000595:Amino Acid Sequence; D001483:Base Sequence; D003593:Cytoplasm / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004352:Drug Resistance, Microbial; D004996:Ethidium / Q000494:pharmacology; D018628:Gene Dosage; D005800:Genes, Fungal / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010641:Phenotype; D010843:Pichia / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D010957:Plasmids / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D017422:Sequence Analysis, DNA; D020079:Terminal Repeat Sequences / Q000235:genetics; D014466:Ultraviolet Rays
D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases; D004259:DNA-Directed DNA Polymerase; D004996:Ethidium