Linear DNA plasmids were found in the following yeasts: four strains of , one of , one of and four of . In each case, the plasmids were present as a pair of DNA molecules of different sizes. The plasmids of strains were associated with a killer activity and their structure was similar to the known killer plasmids pGKL1 and 2. The plasmids from the other three species were different from pGKL plasmids and showed no killer activity against the yeast species tested so far. In all cases, the linear molecules possessed terminal (probably inverted) repeats and their 5′ ends had a protected structure insensitive to λ exonuclease, while the 3′ ends were accessible to exonuclease III. All these strains could be efficiently cured of the plasmids by ultraviolet irradiation. The plasmids from (pDH1 A and B) and from (pWR1A and B) shared related sequences with some of the killer plasmid genes (encoding the supposed DNA polymerases, RNA polymerase and the chitinase), suggesting related genome organization of these plasmids. The pair of plasmids from (pPE1 A and B) appear to be a distantly related member of the group. This pair showed no sequence homology with other plasmids, except weak homology with the putative RNA polymerase gene of pGKL2. None of the plasmids contained the sequences homologous to ORF3 and ORF4 of pGKL1 encoding the toxin resistance determinant and the toxin γ subunit, respectively.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error