仿刺参MyD88依赖途径基因的序列比较和表达分析

为探索仿刺参体内免疫调控机制,对TLR信号通路MyD88依赖途径中Toll、MyD88、IRAK4、TRAF6、P105和Rel的氨基酸序列保守结构域进行了比较分析,找到上下游基因之间可能的互作位点。采用实时荧光定量PCR的方法检测仿刺参体腔细胞中这6个基因在灿烂弧菌刺激后4个时间点的表达模式。试验结果显示,Toll在12 h表达小幅上调,在其他时间点都处于被抑制的状态;MyD88和TRAF6的表达模式基本一致,在12 h表达水平最高;IRAK4在12 h表达上调,在48 h恢复到初始状态;P105和Rel是NFκB的两个同源物,具有相似的结构域,并且这两个基因表达模式一致。通过基因序列和表达模式的对比分析发现,仿刺参体内存在一条高度保守的TLR信号通路。在应对灿烂弧菌入侵时,该通路上的6个基因协同合作参与了机体信号转导和免疫应答的过程。

Sequences Comparison and Expression Analysis of Genes Involved in MyD88 Dependent Pathway in Sea Cucumber Apostichopus japonicus

Amino acid sequences comparison of Toll,MyD88,IRAK4,TRAF6,P105 and Rel in Toll like receptor signaling pathway was performed on their conserved domains in sea cucumber Apostichopus japonicus to seek for interaction sites in order to explore the immune regulation mechanism of sea cucumber.Quantitative real-time PCR was selected to examine genes expression in coelomocytes of sea cucumber challenged with pathogen Vibrio splendidus.It was found that the expression levels of Toll were all inhibited except in significant up-regulation in 12 h challenge.MyD88 and TRAF6 showed consistent expression pattern and were up-regulated to the top point in 12 h challenge.IRAK4 was up-regulated at 12 h and recovered at 48 h.Rel and P105 were homologues of NFκB with similar domains and showed the same expression pattern.The comparisons of amino acid sequences revealed that there was a conserved TLR signaling pathway.After V.splendidus challenge,these six genes were collaboratively involved in signal transduction and immune response in sea cucumber.