Mucin biosynthesis - Bovine C2GnT-M gene, tissue-specific expression, and herpes virus-4 homologue
Mucin biosynthesis - Bovine C2GnT-M gene, tissue-specific expression, and herpes virus-4 homologue
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DOI：
10.1165/rcmb.2003-0202oc
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发表时间：
2004-05-01
影响因子：
6.4
通讯作者：
Cheng, PW
中科院分区：
文献类型：
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作者：
Choi, KH;Osorio, FA;Cheng, PW
粘蛋白聚糖是粘蛋白功能的主要决定因素。粘蛋白聚糖分支结构是由β - 6 n -乙酰氨基葡萄糖转移酶（β - 6gnt）形成的β - 6 n -乙酰氨基葡萄糖胺延伸而来，增加了结构的异质性，从而增加了功能潜力。core2 β - 6gnt - m （C2GnT-M）是唯一能合成所有已知的粘蛋白β - 6 n -乙酰氨基葡萄糖的分支酶。我们报道了四种不同的牛(b) C2GnT-M转录本的克隆，这些转录本仅在5'-非翻译区不同。两种bC2GnT-M转录本仅在气管上皮和睾丸中发现，而其他两种转录本在所有其他粘液分泌组织中发现。bC2GnT-M基因包含4个外显子，全长5.3 kb，整个开放阅读框位于一个外显子内。bC2GnT-M ORF序列分别与牛疱疹病毒4型（BHV-4）、人和大鼠的C2GnT-Ms序列同源性分别为95%、83%和75%。牛与BHV-4 C2GnT-M基因的同源性位于病毒基因ATG起始密码子上游170个核苷酸和TGA终止密码子下游114个核苷酸之间。BHV-4 C2GnT-M基因定位于病毒基因组的非保守区域，是唯一已知的病毒C2GnT-M基因。结果表明BHV-4的C2GnT-M基因来源于牛基因。病毒获得bC2GnT-M基因的机制以及C2GnT-M基因在该病毒存活和发病中的作用仍有待阐明。
Mucin glycans are the major determinant of mucin functions. Mucin glycan branch structures, which increase structural heterogeneity and thus functional potential, are extended from beta6 N-acetylgluco-saminides formed by beta6 N-acetylglucosaminyltransferases (beta6GnT). Core 2 beta6GnT-M (C2GnT-M) is the only branching enzyme that can synthesize all known mucin beta6 N-acetylglucosaminides. We report the cloning of four different bovine (b) C2GnT-M transcripts that are different only at 5'-untranslated regions. Two bC2GnT-M transcripts are found exclusively in tracheal epithelium and testis, whereas the other two are found in all other mucus-secreting tissues. The bC2GnT-M gene contains four exons spanning 5.3 kb and the entire open reading frame is in one exon. The bC2GnT-M ORF has 95,83, and 75% sequence identity to those of bovine herpes virus type 4 (BHV-4), human, and rat C2GnT-Ms, respectively. The homology between bovine and BHV-4 C2GnT-M genes is in the region between 170 nucleotides upstream from ATG start codon and 114 nucleotides downstream from TGA stop codon of the viral gene. Localized at the nonconserved region of the viral genome, the BHV-4 C2GnT-M gene is the only known viral C2GnT-M gene. The results suggest that BHV-4 acquired its C2GnT-M gene from the bovine gene. The mechanism of the viral acquisition of bC2GnT-M gene and the roles of the C2GnT-M gene in the survival and pathogenesis of this virus remain to be elucidated.