Department of Biological Sciences, National University of Singapore, 14 Science Drive, 117543, Singapore; Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, 117604, Singapore.
Department of Biological Sciences, National University of Singapore, 14 Science Drive, 117543, Singapore; Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, 117604, Singapore; National University of Singapore Suzhou Research Institute, Suzhou, Jiangsu, 215123, China.
Fish Shellfish Immunol. 2020 Sep;104:18-24. doi: 10.1016/j.fsi.2020.05.035. Epub 2020 May 28.
Understanding the functions of genes related to disease resistance and identifying polymorphisms in these genes are essential in molecular breeding for disease resistance. Viral nervous necrosis (VNN) is one of the major diseases in the Asian seabass, Lates calcarifer. Our previous works on QTL mapping, GWAS and cell-line transcriptome analysis of the Asian seabass after NNV challenge revealed that the gene GAB3 might be a candidate gene for VNN resistance. In this study, we cloned and characterized GAB3, and identified SNPs in the gene of the Asian seabass. The cDNA of the gene was 2165 bp, containing an ORF of 1674 bp encoding 557 amino acids. The gene consisted of 10 exons and nine introns. It was ubiquitously expressed in normal fish. An analysis of the association between two SNPs in the second intron and NNV resistance in 1035 fish descended from 43 families revealed that the two SNPs were significantly associated with VNN resistance. After NNV infection, the expression of GAB3 was significantly increased in the brain, spleen, muscle and gut, and was suppressed in the liver. The GAB3 protein was localized in the nucleus. Overexpression of GAB3 with specific GAB3-pcDNA was positively correlated to increased viral RNA and titer in NNV-infected Asian seabass cells. Our study provides new evidence to support that GAB3 may be an important gene related to NNV resistance. In addition, the SNPs provide DNA markers for the selection of candidate genes resistance to NNV at the juvenile stage of Asian seabass.
了解与抗病性相关的基因的功能，并鉴定这些基因中的多态性，这在抗病性的分子育种中是至关重要的。病毒性神经坏死症（VNN）是亚洲鲈鱼（Lates calcarifer）的主要疾病之一。我们之前对亚洲鲈鱼在神经坏死病毒（NNV）挑战后的 QTL 作图、全基因组关联分析和细胞系转录组分析的工作表明，GAB3 基因可能是 VNN 抗性的候选基因。在本研究中，我们克隆和表征了 GAB3，并鉴定了亚洲鲈鱼基因中的 SNPs。该基因的 cDNA 长 2165bp，包含一个 1674bp 的开放阅读框，编码 557 个氨基酸。该基因由 10 个外显子和 9 个内含子组成。它在正常鱼类中广泛表达。对来自 43 个家系的 1035 条鱼的第二个内含子中的两个 SNPs 与 NNV 抗性之间的关联分析表明，这两个 SNPs 与 VNN 抗性显著相关。在 NNV 感染后，GAB3 在大脑、脾脏、肌肉和肠道中的表达显著增加，而在肝脏中的表达则受到抑制。GAB3 蛋白定位于细胞核。用特异性 GAB3-pcDNA 过表达 GAB3 与感染 NNV 的亚洲鲈鱼细胞中病毒 RNA 和滴度的增加呈正相关。我们的研究提供了新的证据支持 GAB3 可能是与 NNV 抗性相关的重要基因。此外，这些 SNPs 为亚洲鲈鱼幼鱼期选择抗 NNV 的候选基因提供了 DNA 标记。
