Interaction between mitochondrial DNA and mitochondrial plasmids in Claviceps purpurea: analysis of plasmid-homologous sequences upstream of the lrRNA-gene.

Homology of two linear, mitochondrial (mt) Claviceps purpurea plasmids, pClK1 and pClT5, to the upstream region of the large ribosomal RNA gene in the mtDNA of three strains (W3, T5 and K) has been investigated in detail to explore the widespread phenomenon of homology between mt plasmids and mtDNA in C. purpurea. Sequence comparison indicates that recombination between free plasmids and mtDNA is the cause of the observed homology. The process is similar to the integration of the structurally related adenoviruses into the mammalian genome. As in other fungi, palindromic sequences seem to be involved in this mitochondrial recombination process.