Lollier M, Jaquet L, Nedeva T, Lacroute F, Potier S, Souciet J L
Laboratoire de Microbiologie et de Génétique, URA n-1481 Université Louis-Pasteur/CNRS, Strasbourg, France.
Curr Genet. 1995 Jul;28(2):138-49. doi: 10.1007/BF00315780.
The organisation of the URA1 gene of Schizosaccharomyces pombe was determined from the entire cDNA cloned by the transformation of an ATCase-deficient strain of Saccharomyces cerevisiae. The URA1 gene encodes the bifunctional protein GLNase/CPSase-ATCase which catalyses the first two steps of the pyrimidine biosynthesis pathway. The complete nucleotide sequence of the URA1 cDNA was elucidated and the deduced amino-acid sequence was used to define four domains in the protein; three functional domains, corresponding to GLNase (glutamine amidotransferase), CPSase (carbamoylphosphate synthetase) and ATCase (aspartate transcarbamoylase) activities, and one cryptic DHOase (dihydroorotase) domain. Genetic investigations confirmed that both GLNase/CPSase and ATCase activities are carried out by the same polypeptide. They are also both feedback-inhibited by UTP (uridine triphosphate). Its organization and regulation indicate that the S. pombe URA1 gene product appears very similar to the S. cerevisiae URA2 gene product.
粟酒裂殖酵母URA1基因的组织情况是通过将酿酒酵母的天冬氨酸转氨甲酰酶缺陷菌株进行转化后克隆出的完整cDNA来确定的。URA1基因编码双功能蛋白谷氨酰胺酶/氨甲酰磷酸合成酶-天冬氨酸转氨甲酰酶，该酶催化嘧啶生物合成途径的前两个步骤。已阐明URA1 cDNA的完整核苷酸序列，并利用推导的氨基酸序列确定了该蛋白中的四个结构域；三个功能结构域，分别对应谷氨酰胺酶（谷氨酰胺氨基转移酶）、氨甲酰磷酸合成酶和天冬氨酸转氨甲酰酶的活性，以及一个隐蔽的二氢乳清酸酶结构域。遗传学研究证实，谷氨酰胺酶/氨甲酰磷酸合成酶和天冬氨酸转氨甲酰酶的活性均由同一多肽执行。它们也均受到三磷酸尿苷（UTP）的反馈抑制。其组织和调控表明，粟酒裂殖酵母URA1基因产物与酿酒酵母URA2基因产物非常相似。
