太平洋牡蛎(Crassostrea gigas)类FUT2基因的克隆与组织表达

Molecular Cloning and Expression of FUT2-like Gene in the Oyster(Crassostrea gigas)

通过同源克隆的方法获得太平洋牡蛎(Crassostrea gigas)类FUT2基因的c DNA序列,分析其在牡蛎中的组织表达差异。研究结果表明,太平洋牡蛎类FUT2基因c DNA全长为1941 bp,包含180 bp的5'非翻译区、1086 bp的编码361个氨基酸的开放阅读框及675 bp的3'非翻译区。分子进化聚类分析结果显示,太平洋牡蛎类FUT2基因与家鼠(Mus musculus)等哺乳动物的FUT2基因聚为1个分支。此外,类FUT2基因m RNA在太平洋牡蛎成贝的肝胰脏、闭壳肌、外套膜、唇瓣、鳃等5个组织中均有分布,其中在唇瓣中的表达量最低,在其余4个组织中的表达量差异不显著。本研究表明,牡蛎中类A型组织血型抗原HBGA很可能存在与人A型HBGA相似的合成途径,可为进一步探索牡蛎特异性富集诺如病毒No V的分子机制奠定研究基础。

Norovirus （NoV） is the most common pathogen of acute viral gastroenteritis worldwide, which causes serious issues on public health and food safety. Histo-blood group antigens （HBGAs） have been recognized as receptors of NoV. It has been reported that type A-like HBGA presents in oyster gastrointestinal cells and induces specific accumulation of NoV in oysters. Alpha-1,2-fucosyltransferase （FUT2） is one of the key enzymes required in the HBGA synthesis. However, studies on FUT2 in oysters and other aquatic animals have been lacking. In this study, we cloned the FUT2-like gene in oysters （Crassostrea gigas） using homologous gene sequence method, and also analyzed the expression of FUT2-like gene in five tissues, including hepatopancrea, adductor muscle, mantle, labial palp and gills. The FUT2-like cDNA has a full length of 1941 bp, including a180-bp 5＇-untranslated region （UTR）, a 1086-bp open reading frame （ORF） that encodes a protein of 361 amino acids, and a 675-bp 3＇-untranslated region （UTR）. The molecular evolution analysis showed that the FUT2-like gene in oyster should be categorized into the same branch as FUT2 genes in Mus musculus and other mammals. The expression pattern of FUT2-like gene was analyzed in 5 tissues mentioned above. The results showed that the mRNAs of this gene were expressed in all 5 tissues; the expression level in labial palp was significantly lower than that in the other 4 tissues. Our results indicated that A-like HBGA in oyster might have a similar biosynthesis pathway as Type A HBGA in human. Our study should provide insights into the molecular mechanism of the accumulation of NoV in oysters.