title: Transformation of Saccharomyces cerevisiae with linear DNA killer plasmids from Kluyveromyces lactis.
abstract: Protoplasts of Saccharomyces cerevisiae were mixed with linear DNA plasmids, pGKl1 and pGKl2, isolated from a Kluyveromyces lactis killer strain and treated with polyethylene glycol. Out of 2,000 colonies regenerated on a nonselective medium, two killer transformants were obtained. The pGKl plasmids and the killer character were stably maintained in one (Pdh-1) of them. Another transformant, Pdl-1, was a weak killer, and the subclones consisted of a mixture of weak and nonkiller cells. The weak killers were characterized by the presence of pGKl1 in a decreased amount, and nonkillers were characterized by the absence of pGKl1. The occurrence of two new plasmids which migrated faster than pGKl1 in an agarose gel was observed in Pdl-1 and its subclones, whether weak or nonkillers. Staining with 4',6-diamidino-2-phenylindole revealed that the pGKl plasmids exist in the cytosol of transformant cells with numerous copy numbers.
mesh_terms: D001203:Ascomycota / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics*; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D004718:Saccharomycetales / Q000235:genetics* / Q000254:growth & development; D014169:Transformation, Bacterial
chemical_list: D004271:DNA, Fungal