文章基本信息

标题：Protein glycosylation in yeast: transcript heterogeneity of the ALG7 gene
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作者：M A Kukuruzinska ; P W Robbins
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1987
卷号：84
期号：8
页码：2145-2149
DOI：10.1073/pnas.84.8.2145
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The first enzyme in the lipid-linked oligosaccharide biosynthetic pathway, UDP-N-acetylglucosamine-dolichyl-phosphate N-acetylglucosaminephosphotransferase (UDP-N-acetyl-D-glucosamine:dolichyl-phosphate-N-acetyl- D-glucosaminephosphotransferase, EC 2.7.8.15 ), is encoded by the ALG7 gene. We show that this gene is essential for cell growth, since a null mutation constructed with standard gene disruption techniques results in cell lethality. The ALG7 gene is transcribed into two major messages, approximately 1.38 and 1.56 kilobase pairs (kbp) in size, and this heterogeneity has been mapped to the 3' untranslated region. Two sets of tripartite sequences implicated in transcription termination begin 15 bp and 256 bp past the translation stop codon, TGA. The ratios of the two major transcripts change with gene dosage, with the longer mRNA becoming more abundant in cells containing higher levels of the ALG7 gene. Changes in transcript ratios are also observed in mutants defective in lipid-linked sugar-donor biosynthesis. In addition, there is 5' heterogeneity in the ALG7 mRNAs. The transcripts start at four initiation sites located within a 20-bp region. Two potentially functional TATA elements have been identified at positions -157 and -139, which may be involved in initiation from multiple sites. These features point to numerous factors that may be involved in the regulation of the expression of the ALG7 gene.