Hohmann S, Zimmermann F K
Institut für Mikrobiologie, Technische Hochschule Darmstadt, Federal Republic of Germany.
Curr Genet. 1986;11(3):217-25. doi: 10.1007/BF00420610.
Six unlinked loci for invertase structural genes are known in the yeast Saccharomyces cerevisiae: SUC1-SUC5 and SUC7. These genes are similar in structure and expression but not identical. Different yeast strains possess none, one or several of these genes. We have isolated the genes SUC1-SUC5, subcloned them into the multicopy vector YEp24 and compared the expression of the five SUC genes in one recipient strain. SUC2 was isolated by transformation of a suc0 strain with a gene pool and complementation to sucrose fermentation. SUC4 was cloned from a minipool of chromosomal fragments which were shown to contain SUC4 by Southern hybridization. SUC1, SUC3 and SUC5 were isolated using the method of plasmid eviction. A plasmid containing regions flanking SUC4 was integrated next to these SUC genes. The plasmid together with the SUC genes were then cut out of the chromosome using an appropriate restriction endonuclease. The length of chromosomal DNA fragments containing the different SUC genes were 4.8 kb for SUC1, 5.2 kb for SUC2, 4.8 kb for SUC3, 12.8 kb for SUC4 and 17.2 kb for SUC5. Fragments containing the complete SUC genes and the sequences controlling their expression were subcloned into YEp24 and transformed into a strain without any active invertase gene. Invertase activity of transformants was measured after growth repressing (8% glucose) and derepressing (2% raffinose) conditions. As expected from results with strains carrying the individual SUC genes in a chromosomal location, the SUC genes were expressed to a different extent.
在酿酒酵母中，已知有6个与转化酶结构基因不连锁的位点：SUC1 - SUC5和SUC7。这些基因在结构和表达上相似但并不完全相同。不同的酵母菌株拥有这些基因中的无、一个或几个。我们已经分离出了SUC1 - SUC5基因，将它们亚克隆到多拷贝载体YEp24中，并比较了这5个SUC基因在一个受体菌株中的表达情况。SUC2是通过用基因库转化suc0菌株并互补蔗糖发酵而分离得到的。SUC4是从一组染色体片段小池中克隆出来的，通过Southern杂交显示这些片段含有SUC4。SUC1、SUC3和SUC5是用质粒排除法分离得到的。一个含有SUC4侧翼区域的质粒被整合到这些SUC基因旁边。然后使用合适的限制性内切酶将该质粒与SUC基因一起从染色体上切下。含有不同SUC基因的染色体DNA片段长度分别为：SUC1为4.8 kb，SUC2为5.2 kb，SUC3为4.8 kb，SUC4为12.8 kb，SUC5为17.2 kb。含有完整SUC基因及其表达调控序列的片段被亚克隆到YEp24中，并转化到一个没有任何活性转化酶基因的菌株中。在生长抑制（8%葡萄糖）和去抑制（2%棉子糖）条件下测定转化子的转化酶活性。正如从在染色体位置携带单个SUC基因的菌株所得到的结果所预期的那样，SUC基因的表达程度不同。
