Identification and characterization of a novel Toll-like receptor 2 homologue in the large yellow croaker Larimichthys crocea
Identification and characterization of a novel Toll-like receptor 2 homologue in the large yellow croaker Larimichthys crocea
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大黄鱼中新型 Toll 样受体 2 同源物的鉴定和表征
DOI：
10.1016/j.fsi.2015.11.002
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发表时间：
2016-01-01
影响因子：
4.7
通讯作者：
Chen, Xinhua
中科院分区：
文献类型：
--
作者：
Ao, Jingqun;Mu, Yinnan;Chen, Xinhua
Toll样受体是天然免疫的重要组成部分，在抵御病原体入侵的免疫防御中发挥着重要作用。在本研究中，我们在大黄鱼(Larimichthys Crocea)中发现了一个新的TLR2同源物(LycTLR2b)，它与以前报道的大黄鱼TLR2(暂定为LycTLR2a)具有较低的序列同源性。LycTLR2b基因全长2926个核苷酸，编码797个氨基酸。LycTLR2b蛋白具有典型的TLR结构域结构，包括一个信号肽、胞外区的7个富含亮氨酸重复序列(LRR)、跨膜区和胞内区的Toll-IL-1受体(TIR)结构域。系统发育分析表明，LycTLR2a和LycTLR2b都属于一个由所有TLR2序列组成的主要分支，并被分为两个不同的分支。基因组组织发现LycTLR2b基因没有内含子，这与斑马鱼和人类的TLR2基因相似，而LycTLR2a基因含有多个内含子，与斑马鱼的TLR2a和河豚的TLR2基因一样。Syntenic分析表明，LycTLR2a和LycTLR2b的发生可能是相对较新的基因组复制事件的结果。LycTLR2b在所有被检测的组织中都有结构性表达，尽管表达水平不同。在细菌疫苗攻击后，LycTLR2b在脾和头肾组织中的表达水平显著上调。综上所述，这些结果表明大黄鱼体内存在两种不同的TLR2同源物，它们可能在抗菌免疫中发挥作用。(C)2015爱思唯尔有限公司。保留所有权利。
Toll-like receptors (TLRs) are key components of innate immunity that play significant roles in immune defence against pathogen invasion. In the present study, we identified a novel TLR2 homologue (LycTLR2b) in large yellow croaker (Larimichthys crocea) that shared low sequence identity with the previously reported large yellow croaker TLR2 (tentatively named LycTLR2a). The full-length cDNA of LycTLR2b was 2926 nucleotides (nt) long and encoded a protein consisting of 797 amino acids (aa). The deduced LycTLR2b protein exhibited a typical TLR domain architecture including a signal peptide, seven leucine-rich repeats (LRRs) in the extracellular region, a transmembrane domain, and a Toll-Interleukin 1 receptor (TIR) domain in the cytoplasmic region. Phylogenetic analysis showed that both LycTLR2a and LycTLR2b fall into a major clade formed by all TLR2 sequences, and are divided into two distinct branches. Genomic organization revealed that the LycTLR2b gene lacks intron, which is similar to zebrafish and human TLR2 genes, whereas the LycTLR2a gene contains multiple introns, as found in damselfish TLR2a and Fugu TLR2 genes. Syntenic analysis suggested that the occurrence of LycTLR2a and LycTLR2b may result from a relatively recent genome duplication event. LycTLR2b mRNA was constitutively expressed in all tissues examined although at different levels. Following bacterial vaccine challenge, LycTLR2b expression levels were significantly up-regulated in both spleen and head kidney tissues. Taken together, these results indicated that two different TLR2 homologues, which may play roles in antibacterial immunity, exist in large yellow croaker. (C) 2015 Elsevier Ltd. All rights reserved.