title: Evidence for giant linear plasmids in the ascomycete Podospora anserina.
abstract: In the extrachromosomal mutant AL2 of the ascomycete Podospora anserina longevity is correlated with the presence of the linear mitochondrial plasmid pAL2-1. In addition to this autonomous genetic element, two types of closely related pAL2-1-homologous molecules were detected in the high-molecular-weight mitochondrial DNA (mtDNA). One of these molecules is of linear and the other of circular structure. Both molecules contain pAL2-1 sequences which appear to be integrated at the same site in the mtDNA. Sequence analysis of a DNA fragment cloned from one of these molecules revealed that it contains an almost full-length copy of pAL2-1. At the site of plasmid integration a 15-nucleotide AT-spacer and long inverted mtDNA sequences were identified. Finally, two giant linear plasmid-like DNAs of about 50 kbp and 70 kbp were detected in pulsed-field gels of mutant AL2. These molecules are composed of mtDNA and pAL2-1-specific sequences and may result from the integration of mtDNA sequences into linear plasmid pAL2-1.
authors.affiliation: Department of Molecular Biology of the Aging Processes, German Cancer Research Center, Heidelberg.
authors.forename: J
authors.initials: J
authors.lastname: Hermanns
authors.forename: A
authors.initials: A
authors.lastname: Asseburg
authors.forename: H D
authors.initials: HD
authors.lastname: Osiewacz
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D003573:Cytochrome b Group / Q000235:genetics; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D016521:Electrophoresis, Gel, Pulsed-Field; D005092:Exonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010957:Plasmids / Q000737:chemistry / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D013098:Xylariales / Q000235:genetics* / Q000254:growth & development
chemical_list: D003573:Cytochrome b Group; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D005092:Exonucleases