Physical and genetic characterization of linear DNA plasmids from the heterothallic yeast Saccharomycopsis crataegensis.
Five strains of the heterothallic yeast Saccharomycopsis crataegensis have been previously shown to contain DNA and/or RNA plasmidlike molecules (Shepherd et al. 1987). Three DNA plasmids, designated pScrl-1, -2 and -3, were found in strain NRRL Y-5902, while two were identified in each of NRRL strains Y-5903 and Y-5904. DNA plasmids were not identified in S. crataegensis strains Y-5910 or YB-192. Four S. crataegensis strains (Y-5903, Y-5904, Y-5910 and YB-192) were also shown to possess double-stranded RNA (dsRNA) molecules not found in strain Y-5902 (Shepherd et al. 1987). Hybridization studies now demonstrate the DNA plasmids in Y-5903 and Y-5904 to be highly homologous to their respective size counterparts (pScrl-1 and pScrl-2) in Y-5902 and to show some homology to pScrl-3. Restriction endonuclease mapping studies confirm the linear nature of each plasmid and establish identical restriction maps for a 1.4 kilobase (kb) region in pScrl-2 and -3. This 1.4 kb region accounts for the hybridization homology of pScrl-2 and pScrl-3 noted by Shepherd et al. (1987) and for homology of the plasmids of Y-5903 and Y-5904 to pScrl-3 of Y-5902. The pScrl plasmids show no homology to the dsRNA molecules of S. crataegensis, the 2 microM circular DNA of Staccharomyces cerevisiae, the 'killer' plasmids of Kluyveromyces lactis, or the linear DNA plasmids of Pichia inositovora. In crosses between linear DNA plasmid-containing and dsRNA-containing strains, only progeny containing the pScrl plasmids were recovered. Poor spore viability and a lack of complete tetrad recovery limited the extent of the analysis, but the findings suggest a cytoplasmic mode of inheritance for these linear DNAs.
Bolen
P L
PL
National Center for Agricultural Utilization Research, U.S. Department of Agriculture, Peoria, Illinois 61604.
Kurtzman
C P
CP
Ligon
J M
JM
Mannarelli
B M
BM
Bothast
R J
RJ
D015152:Blotting, Northern; D004271:DNA, Fungal / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D005800:Genes, Fungal; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics*; D012330:RNA, Double-Stranded / Q000235:genetics; D012331:RNA, Fungal / Q000235:genetics; D015183:Restriction Mapping; D012442:Saccharomycopsis / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic
D004271:DNA, Fungal; D012330:RNA, Double-Stranded; D012331:RNA, Fungal