Trumbly R J
Department of Biochemistry, Medical College of Ohio, Toledo 43699.
Gene. 1988 Dec 15;73(1):97-111. doi: 10.1016/0378-1119(88)90316-2.
Mutations in the CYC8 ( = SSN6) gene of Saccharomyces cerevisiae alleviate glucose repression of many glucose-repressible genes. The gene was isolated by screening for complementation of a cyc8 effect on colony morphology. Subclones containing a 5.3-kb SalI-XbaI fragment provided complete complementation. The gene was further localized to 3.5 kb by mapping of the CYC8 mRNA and insertional mutagenesis. Insertion and deletion mutations are viable and produce the same array of phenotypes as point mutations. CYC8 disruptions also had effects on the mating ability and morphology of MAT alpha cells similar to that of tup1 mutations. The nucleotide sequence of a 4866-bp fragment, including CYC8, was determined. One long open reading frame of 966 amino acid predicts a protein of molecular weight 10,7215. The predicted protein is extremely glutamine-rich, with blocks of 16 and 31 glutamines in tandem at the N and C regions, respectively. The CYC8 gene product lacks consensus sequences for DNA-binding domains, suggesting that its function may be different from classical repressor proteins.
酿酒酵母CYC8（= SSN6）基因的突变可缓解许多葡萄糖可阻遏基因的葡萄糖阻遏作用。通过筛选cyc8对菌落形态的互补作用来分离该基因。含有5.3 kb SalI - XbaI片段的亚克隆提供了完全互补。通过CYC8 mRNA的定位和插入诱变，该基因进一步定位到3.5 kb。插入和缺失突变是可行的，并且产生与点突变相同的一系列表型。CYC8缺失对MATα细胞的交配能力和形态也有影响，类似于tup1突变。测定了包括CYC8在内的4866 bp片段的核苷酸序列。一个966个氨基酸的长开放阅读框预测出一种分子量为107215的蛋白质。预测的蛋白质富含谷氨酰胺，在N端和C端区域分别有16个和31个谷氨酰胺串联组成的区域。CYC8基因产物缺乏DNA结合结构域的共有序列，这表明其功能可能不同于经典的阻遏蛋白。
