Tretiak K A, Zakal'skiĭ A E, Gudz' S P
Lviv State University.
Mikrobiol Z. 1998 Jul-Aug;60(4):57-66.
The gene of beta-galactosidase of lactose-assimilating yeast Candida pseudotropicalis was cloned in pG2 and pBG2-3 hybrid shuttle vectors and expressed in Saccharomyces cerevisiae laboratory strains under the control of own promoter. The plasmids were able to replicate autonomously with relative stability in transformants of baker's yeasts. The availability of glucose or lactose in the medium influenced the recombinant plasmid stability and the expression of the cloned gene. A number of experiments have shown that the LAC+ phenotype in pG2-transformed Saccharomyces cerevisiae was due to the expression of the Candida pseudotropicalis lactose permease gene that is probably located in SaIG1/XhoI DNA fragment about 4.3 kb long. Southern hybridization experiments showed that LAC(+)-transformants of Saccharomyces cerevisiae contained both autonomously-replicative, and integrative pG2 plasmid.
乳糖同化酵母假热带念珠菌的β-半乳糖苷酶基因被克隆到pG2和pBG2 - 3杂交穿梭载体中，并在自身启动子的控制下在酿酒酵母实验室菌株中表达。这些质粒能够在面包酵母转化体中相对稳定地自主复制。培养基中葡萄糖或乳糖的存在会影响重组质粒的稳定性和克隆基因的表达。大量实验表明，pG2转化的酿酒酵母中的LAC +表型是由于假热带念珠菌乳糖通透酶基因的表达，该基因可能位于约4.3 kb长的SaIG1/XhoI DNA片段中。Southern杂交实验表明，酿酒酵母的LAC(+)转化体同时含有自主复制型和整合型pG2质粒。
