Shen Yubang, Fu Gui Hong, Liu Feng, Yue Gen Hua
Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Republic of Singapore.
Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, 201306, China.
Mol Biol Rep. 2015 Dec;42(12):1593-601. doi: 10.1007/s11033-015-3930-6. Epub 2015 Nov 6.
Tilapia is the common name for a group of cichlid fishes. Identification of DNA markers significantly associated with important traits in candidate genes may speed up genetic improvement. L-Amino acid oxidase (LAO) plays a crucial role in the innate immune defences of animals. Previously, whether LAO variants were associated with economic traits had not been studied in fish. We characterized the cDNA sequence of the LAO gene of hybrid tilapia (Oreochromis spp.). Its ORF was 1536 bp, encoding a flavoenzyme of 511 amino acids. This gene consisted of seven exons and six introns. Its expression was detected in the intestine, blood, kidney, skin, liver. It was highly expressed in the intestine. After a challenge with a bacterial pathogen, Streptococcus agalactiae, its expression was up-regulated significantly in the liver, intestine and spleen (P < 0.05). We identified one SNP in the genomic sequence of the gene and found that this SNP was associated significantly with body length (P < 0.05), but not with resistance to S. agalactiae. The results of this study suggest that the LAO gene plays an important role in innate immune responses to the bacterial pathogen in tilapia. The investigation of relationship between polymorphism of LAO gene and disease resistance and growth in tilapia showed that one SNP was associated significantly with body length. Further experiments on whether SNPs in the LAO gene are associated with growth in tilapia and other populations could be useful in understanding more functions of the LAO gene.
罗非鱼是丽鱼科一群鱼类的通称。鉴定与候选基因中重要性状显著相关的DNA标记可能会加速遗传改良。L-氨基酸氧化酶（LAO）在动物的天然免疫防御中起关键作用。此前，尚未在鱼类中研究LAO变体是否与经济性状相关。我们对杂交罗非鱼（奥利亚罗非鱼属）的LAO基因的cDNA序列进行了特征分析。其开放阅读框为1536 bp，编码一种含511个氨基酸的黄素酶。该基因由7个外显子和6个内含子组成。在肠道、血液、肾脏、皮肤、肝脏中检测到其表达。在肠道中高表达。在用细菌病原体无乳链球菌攻击后，其在肝脏、肠道和脾脏中的表达显著上调（P < 0.05）。我们在该基因的基因组序列中鉴定出一个单核苷酸多态性（SNP），发现该SNP与体长显著相关（P < 0.05），但与对无乳链球菌的抗性无关。本研究结果表明，LAO基因在罗非鱼对细菌病原体的天然免疫反应中起重要作用。对LAO基因多态性与罗非鱼抗病性和生长关系的研究表明，一个SNP与体长显著相关。进一步研究LAO基因中的SNP是否与罗非鱼及其他群体的生长相关，可能有助于了解LAO基因的更多功能。
