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绿尾唇鱼(Cheilinus chlorourus)为南海海域重要的经济鱼类，作为肉食性无胃鱼类，绿尾唇鱼不表达胃蛋白酶原基因，为探究β位点淀粉样前体蛋白裂解酶2(Beta-secretase 2,BACE2)是否在绿尾唇鱼中具有水解食物蛋白的功能，本文采用序列特征分析、生物信息学分析和原位杂交技术对绿尾唇鱼bace2基因进行了探究。研究显示：绿尾唇鱼bace2开放阅读框(Open reading frame, ORF)长度为1 530 bp,编码509个氨基酸；BACE2蛋白在鲈形目物种间呈现较高保守性，绿尾唇鱼BACE2蛋白与波纹唇鱼(Cheilinus undulatus)和鳜(Siniperca chuatsi)等鲈形目物种具有较高的同源性；预测绿尾唇鱼BACE2蛋白的相对分子质量为55.27 kDa,等电点为5.10,属于稳定的亲水性蛋白，具有信号肽和2个跨膜结构域，具有3个潜在的N-糖基化位点和6个潜在的O-糖基化位点，二级结构以无规则卷曲为主；qRT-PCR分析显示，bace2基因在肠道中的相对表达量最高；原位杂交显示，绿尾唇鱼bace2在小肠绒毛和隐窝区域中广泛表达；亚细胞定位显示，BACE2主要定位在细胞膜上。研究结果表明，绿尾唇鱼bace2可能由小肠绒毛细胞分泌，并在细胞外的蛋白质水解中起重要作用，研究结果可为绿尾唇鱼消化生理的进一步研究和人工配合饲料开发提供参考。
Abstract：Cheilinus chlorourus is an important economic fish species in South China Sea. As a carnivorous fish species lacking stomach, C. chlorourus does not express the pepsinogen gene. In this study, to investigate whether the β-site amyloid precursor protein cleaving enzyme 2(BACE2) functions in hydrolyzing food proteins in C. chlorourus, we employed several analytical techniques. We utilized sequence feature analysis to characterize the gene structure, bioinformatic analysis to predict protein function, and in situ hybridization to assess gene expression patterns of the BACE2 gene in C. chlorourus. The results showed that bace2 has an open reading frame(ORF) of 1 530 bp, encodes 509 amino acids. The BACE2 is highly conserved in Perciformes. It was highly similar with BACE2 from C. undulatus and Siniperca chuatsi. The predicted molecular weight of the protein was 55.27 kDa, and its isoelectric point was 5.10. It was a stable, hydrophilic protein with a signal peptide and two transmembrane domains. It also had three possible N-glycosylation sites and six possible O-glycosylation sites. Its secondary structure was mainly random coils. QRT-PCR analysis showed that bace2 exhibited the highest relative expression level in intestine. In situ hybridization showed that bace2 widely expressed in villi and intestinal crypt. Subcellular localization revealed that BACE2 primarily localized in cell membrane. These results suggested that BACE2 may be secreted by intestinal villus, contributing to the hydrolysis of extracellular proteins. Our findings provided useful information for studying the digestion of C. chlorourus and developing better artificial feeds.
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基本信息:
DOI：10.16441/j.cnki.hdxb.20240337
中图分类号:S917.4
引用信息:
[1]王秋生,连滢滢,姜天宇,等.绿尾唇鱼bace2基因的克隆、序列分析、表达与亚细胞定位[J].中国海洋大学学报(自然科学版),2026,56(01):29-40.DOI:10.16441/j.cnki.hdxb.20240337.
基金信息:
海南省重点研究发展计划项目(ZDYF2023XDNY037)资助~~