Molecular and phenotypic analysis of the S-cerevisiae MNN10 gene identifies a family of related glycosyltransferases
Molecular and phenotypic analysis of the S-cerevisiae MNN10 gene identifies a family of related glycosyltransferases
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DOI：
10.1093/glycob/6.1.73
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发表时间：
1996-02-01
期刊：
影响因子：
4.3
通讯作者：
Poster, JB
中科院分区：
文献类型：
--
作者：
Dean, N;Poster, JB
酿酒酵母mnn 10突变体在N-连接寡糖的合成中是有缺陷的（Sauzu等人，1989年）。这种突变对O-连接的糖没有影响，但会导致含有严重截短的N-连接外链寡糖的糖蛋白的积累。我们通过互补突变表型所赋予的潮霉素B敏感性克隆了MNN 10基因。序列分析预测Mnn 10 p是一个46.7 kDa的II型膜蛋白，具有糖基转移酶的结构特征。亚细胞分级分离数据表明，大多数的Mnn 10蛋白cofractiates与高尔基体标记和远离标记的内质网（ER），这表明Mnn 10 p是本地化的高尔基复合体。Mnn 10蛋白质序列与两个不同数据库中的蛋白质的比较鉴定了与Mnn 10 p同源的五种蛋白质，包括位于高尔基复合体中的充分表征的粟酒裂殖酵母α 1，2半乳糖基转移酶。两者合计，这些结果表明，MNN 10编码一种新的高尔基体定位的甘露糖基转移酶包含在这个以前未被识别的相关糖转移酶家族。
The Saccharomyces cerevisiae mnn10 mutant is defective in the synthesis of N-linked oligosaccharides (Ballou et al., 1989). This mutation has no effect on O-linked sugars, but results in the accumulation of glycoproteins that contain severely truncated N-linked outer-chain oligosaccharides. We have cloned the MNN10 gene by complementation of the hygromycin B sensitivity conferred by the mutant phenotype. Sequence analysis predicts that Mnn10p is a 46.7 kDa type II membrane protein with structural features characteristic of a glycosyltransferase. Subcellular fractionation data indicate that most of the Mnn10 protein cofractionates with Golgi markers and away from markers for the endoplasmic reticulum (ER), suggesting Mnn10p is localized to the Golgi complex. A comparison of the Mnn10 protein sequence to proteins in the two different databases identified five proteins that are homologous to Mnn10p, including a well characterized Schizosaccharomyces pombe alpha 1,2 galactosyltransferase that resides in the Golgi complex. Taken together, these results suggest that MNN10 encodes a novel Golgi-localized mannosyltransferase contained in this previously unrecognized family of related sugar transferases.