ASPARAGINE-LINKED GLYCOSYLATION IN SACCHAROMYCES-CEREVISIAE - GENETIC-ANALYSIS OF AN EARLY STEP
ASPARAGINE-LINKED GLYCOSYLATION IN SACCHAROMYCES-CEREVISIAE - GENETIC-ANALYSIS OF AN EARLY STEP
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DOI：
10.1128/mcb.4.11.2381
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发表时间：
1984-01-01
影响因子：
5.3
通讯作者：
RINE, J
中科院分区：
文献类型：
--
作者：
BARNES, G;HANSEN, WJ;RINE, J
天冬酰胺连接的糖基化是一种共价修饰形式，其将膜结合或在细胞外的细胞区室中拓扑结构上的蛋白质与在细胞质中保持可溶的那些蛋白质区分开。这种类型的糖基化是逐步发生的，在内质网中加入核心寡糖，随后在高尔基体中进行修饰。衣霉素是合成N-连接寡糖的最早步骤之一的抑制剂，用于选择对该抗生素具有抗性的突变体。遗传学、生物化学和生理学实验得出以下结论。N-连接寡糖的合成是细胞的基本功能。与哺乳动物细胞相反，酵母细胞不通过葡糖胺转运功能转运衣霉素。一个基因，ALG 7，这可能是UDP-N-乙酰葡糖胺-1-P转移酶，被衣霉素抑制的酶的结构基因，被确定。该基因中的显性突变导致转移酶活性增加和细胞形成孢子的能力丧失。此外，还鉴定了另一个基因，TU 1，其中隐性突变导致对衣霉素的抗性。ALG 7和TUN 1基因都定位在染色体VII上。
Asparagine-linked glycosylation is a form of covalent modification that distinguishes proteins that are either membrane bound or in cellular compartments topologically outside of the cell from those proteins that remain soluble in the cytoplasm. This type of glycosylation occurs stepwise, with core oligosaccharide added in the endoplasmic reticulum and subsequent modifications occurring in the Golgi. Tunicamycin, an inhibitor of one of the earliest steps in the synthesis of N-linked oligosaccharide, was used to select for mutants that are resistant to this antibiotic. Genetic, biochemical and physiological experiments led to the following conclusions. The synthesis of N-linked oligosaccharide is an essential function in cells. In contrast to mammalian cells, yeast cells do not transport tunicamycin by a glucosamine transport function. A gene, ALG7, that is probably the structural gene for UDP-N-acetylglucosamine-1-P transferase, the enzyme inhibited by tunicamycin, was identified. Dominant mutations in this gene result in increased activity of the transferase and loss of the ability of the cell to sporulate. In addition, another gene, TUN1, in which recessive mutations result in resistance to tunicamycin, was identified. The ALG7 and TUN1 genes both map on chromosome VII.