The sequence and transcript heterogeneity of the yeast gene ALG1, an essential mannosyltransferase involved in N-glycosylation.
The sequence and transcript heterogeneity of the yeast gene ALG1, an essential mannosyltransferase involved in N-glycosylation.
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DOI：
10.1016/s0021-9258(19)39256-7
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发表时间：
1990-04
期刊：
影响因子：
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通讯作者：
C. Albright;R. Robbins
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文献类型：
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作者：
C. Albright;R. Robbins
酵母基因ALG 1编码甘露糖基转移酶，其通过催化由GDP-Man和Dol-PP-Glc-NAc 2形成焦磷酸多萜醇（Dol-PP）-GlcNAc 2 Man，参与形成用于N-糖基化的脂质连接前体寡糖。对包括ALG 1基因的DNA区域进行测序，发现其含有1347个碱基的开放阅读框。预测的ALG 1蛋白含有449个氨基酸（51.9 kDa），在氨基末端附近具有疏水区域，表明它是一个完整的膜蛋白，和4个潜在的N-糖基化位点。通过插入URA 3基因破坏ALG 1开放阅读框表明ALG 1基因对生存力是必需的。北方分析和转录本保护表明，ALG 1基因转录成两类信使，它们在5'端相差约100个碱基，但有一个共同的3'端。在活跃生长的细胞中，短转录本占主导地位，但随着生长减缓，长转录本更普遍。预测短转录本编码ALG 1蛋白，而预测长转录本编码未知功能的74个氨基酸的蛋白。74个氨基酸的阅读框架，其终止于ALG 1蛋白质的潜在起始密码子上游42个碱基的破坏，表明其对于生存力不是必需的。
The yeast gene ALG1 encodes a mannosyltransferase which participates in the formation of the lipid-linked precursor oligosaccharide for N-glycosylation by catalyzing the formation of dolichol pyrophosphate (Dol-PP)-GlcNAc2Man from GDP-Man and Dol-PP-Glc-NAc2. The DNA region including the ALG1 gene was sequenced and found to contain an open reading frame of 1347 bases. The predicted ALG1 protein contained 449 amino acids (51.9 kDa) with a hydrophobic region near the amino terminus, suggesting it was an integral membrane protein, and four potential sites for N-glycosylation. Disruption of the ALG1 open reading frame by insertion of the URA3 gene showed that the ALG1 gene was essential for viability. Northern analysis and transcript protection showed that the ALG1 gene was transcribed into two classes of messages which differed by about 100 bases at their 5' end and shared a common 3' end. In actively growing cells the short transcript predominated, but as growth slowed the long transcript was more prevalent. The short transcript was predicted to encode the ALG1 protein while the long transcript was predicted to encode a 74-amino acid protein of unknown function. Disruption of the 74-amino acid reading frame, which ended 42 bases upstream of the potential start codon for the ALG1 protein, showed it was not essential for viability.