酵母SUC2基因上游顺序对其表达的影响

The Effects of Upstream Region of SUC2 Gene on Its Expression

从SUC2基因上游约—900bp向起始密码进行系列缺失。将带有这种缺失上游区的SUC2基因插入多拷贝质粒,并转化进不产蔗糖酶的酵母细胞。测定了这些缺失株表达蔗糖酶的数量。结果表明:在葡萄糖阻遏条件下,SUC2上游区缺失从-636bp到-179bp的不同细胞,糖基化蔗糖酶的表达量逐渐升高。和野生型相比,SUC2上游区缺失到-223bp和-179bp的细胞糖基化蔗糖酶量增加100倍以上。在葡萄糖去阻遏条件下,SUC2上游缺失从-395bp到-179bp的不同细胞,糖基化蔗糖酶的表达量只显示微弱的去阻遏效应。缺失末端达-89bp和-41bp的细胞只表达很少的糖基化蔗糖酶,但是非糖基化蔗糖酶的表达量明显增加。

A series of deletions were made at upstream region of SUC2 gene wkh the direction from about - 900bp to the initiation codon. The DNA fragments, which contain SUC2 gene and its deleted upstream region, were inserted into multicopy plasmid. After transforming resulted plasmid into SUC strain, the invertase activities produced by the transformants were determined.Under glucose repressing condition, the glycosylated invertase produced by transformants with deletion from -636bp to - 179bp of SUC2 gene were gradually increased. The transformants with deletion down to - 223bp and - 179bp could produce about 100 times higher glycosylated invertase activity as compared to wild type.Under glucose derepressing condition, the glycosylated invertase produced by transform-ants with deletion from - 395bp to - 179bp of SUC2 gene were only slightly more than that produced under glucose repressing condition.Under either glucose repressing or derepressing condition, the transformants with dele-tionat -89bp and -41bp produced only a little of glycosylated invertase, while they produced remarkably higher nonglycosylated inverta-se activity.