National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China.
National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan 316022, PR China.
Fish Shellfish Immunol. 2018 Jul;78:331-337. doi: 10.1016/j.fsi.2018.04.058. Epub 2018 Apr 27.
Toll-like receptor (TLR) is considered to be an evolutionarily conserved transmembrane protein which promotes the Toll signal pathway to active the expression of transcription factors in the innate immunity of the organism. In this study, a full length of TLR homologue of 2525bp in Mytilus coruscus (named as McTLR-a, GenBank accession no: KY940571) was characterized. Its ORF was 1815 bp with a 5'untranslated region (UTR) of 128 bp and a 3'UTR of 582 bp, encoding 602 amino acid residues with a calculated molecular weight of 70.870 kDa (pI = 6.10). BLASTn analysis and phylogenetic relationship strongly suggested that this cDNA sequence was a member of TLR family. Quantitative real time RT-PCR showed that constitutive expression of McTLR-a was occurred, with increasing order in hemocyte, gonad, mantle, adducter, gill and hepatopancreas. Bacterial infection and heavy metals stimulation up-regulated the expression of McTLR-a mRNA in hepatopancreas with time-dependent manners. The maximum expression appeared at 12 h after pathogenic bacteria injection, with approximately 22-fold in Aeromonas hydrophila and 17-fold in Vibrio parahemolyticus higher than that of the blank group. In heavy metals stress group, they all reached peaks at 3d, while the diverse concentration caused the maximum expression were different. The highest expression reached approximately 7-fold higher than the blank in low concentration of Pb exposure. In Cu treated group, it reached the peak (approximately 12-fold higher than the blank)in middle concentration. These results indicated that McTLR-a might be involved in the defense response and had a significant role in mediating the environmental stress.
Toll 样受体（TLR）被认为是一种进化上保守的跨膜蛋白，它促进 Toll 信号通路，激活生物体固有免疫中的转录因子的表达。在本研究中，我们对来自贻贝（Mytilus coruscus）的全长 TLR 同源物（命名为 McTLR-a，GenBank 登录号：KY940571）进行了特征分析。其 ORF 为 1815bp，包含 5'非翻译区（UTR）128bp 和 3'UTR 582bp，编码 602 个氨基酸残基，预测分子量为 70.870 kDa（pI=6.10）。BLASTn 分析和系统发育关系强烈表明，该 cDNA 序列是 TLR 家族的一员。定量实时 RT-PCR 显示 McTLR-a 呈组成性表达，在血细胞、性腺、套膜、闭壳肌、鳃和肝胰腺中表达量逐渐增加。细菌感染和重金属刺激可使肝胰腺中 McTLR-a mRNA 的表达呈时间依赖性上调。在致病菌注射后 12 h 达到最大值，与空白组相比，嗜水气单胞菌和副溶血弧菌分别增加了约 22 倍和 17 倍。在重金属应激组中，它们都在 3d 时达到峰值，而不同浓度导致的最大表达量也不同。在低浓度 Pb 暴露下，最高表达量约为空白组的 7 倍。在 Cu 处理组中，在中等浓度下达到峰值（约比空白组高 12 倍）。这些结果表明，McTLR-a 可能参与防御反应，并在介导环境应激中具有重要作用。
