pSH-CUP重组质粒的构建及面包酵母酸性海藻糖酶基因的敲除

Constructing Recombinant Plasmid pSH-CUP and Knockout of Acid Trehalase Gene in Baker's Yeast

设计含有与面包酵母(Saccharomyces cerevisiae BY-6)编码酸性海藻糖酶ATH基因内部部分序列同源的长引物,以质粒pUG6为模板进行PCR构建带有Cre/loxP系统的敲除单元,转化面包酵母获得G418阳性克隆。将铜抗性基因(CUP1-MT1)导入Cre重组酶表达质粒pSH47,得到重组质粒pSH-CUP,并转化阳性克隆,以铜抗性筛选面包酵母转化子。半乳糖诱导表达Cre酶切除Kan^r基因。重组质粒pSH-CUP的构建,不仅解决了酵母转化子筛选标记问题和非酵母基因的引入,而且使LoxP-kanMX-loxP基因敲除体系在进行真核生物基因敲除时更加方便可行。

The ATHI gene encoded acid trehalase in Saccharomyces cerevisiae. The gene disruption cassette combined the heterologous dominant kanr resistance marker with a Cre/loxP-mediated marker removal procedure. The gene disruption cassette was produced by PCR using the same long oligonucleotides comprising 50 nucleotides that annealed to sites upstream or downstream of the genomic target sequence to be deleted. After transformation of the linear disruption cassettes with a Cre/loxP-mediated marker into the cells of Saccharomyces cerevisiae BY-6, selected transformants were checked by PCR for correct the integration of the cassette and concurrent deletion of the chromosomal target sequence. The copper-resistance gene （CUP1-MT1） was cloned into pSH47, which yielded pSH-CUP. The recombinant plasmid pSH-CUP was transformed into the cells of Saccharomyces cerevisiae BY-6（A ATHI, G418^r）, and transformants were selected for copper resistance. Upon expression of the Cre recombinase results in removal of the kanr gene, leaving behind a single loxP site at the chromosomal locus. Construction of the recombinant plasmid pSH-CUP avoided inserting don-yeast gene and made the loxP - kanMX - loxP gene disruption cassette more conventional for eukaryotic organism gene disruption.