三疣梭子蟹(Portunus trituberculatus)CTL基因SNP位点E4-205 C/T与抗溶藻弧菌相关性分析

C-型凝集素(C-typelectin,CTL)是甲壳类动物体液免疫中重要的免疫因子之一。但CTL基因在溶藻弧菌对三疣梭子蟹(Portunustrituberculatus)感染的过程中的表达及抗病机制尚有待进一步研究。为初步阐明CTL基因SNP E4-205 C/T位点与抗溶藻弧菌感染相关的分子机制,对不同基因型梭子蟹进行溶藻弧菌感染,通过绝对定量方法分析不同基因型梭子蟹肝胰腺、肌肉组织中溶藻弧菌的复制情况。发现溶藻弧菌感染后12 h内梭子蟹肝胰腺、肌肉组织中C/C组细菌数量显著高于T/T组,结果表明T/T组梭子蟹抗感染能力显著高于C/C组。进一步对该位点非同义突变(ACT-ATT)导致的一个氨基酸改变(Thr-Ile)的两种蛋白进行体外重组表达,并对两种重组蛋白CTL-ATT及CTL-ACT进行活性分析。发现两种重组蛋白对溶藻弧菌生长均具有一定的抑制作用, CTL-ATT的抑菌活性显著高于CTL-ACT。重组蛋白CTL-ATT与PAMPs的结合活性高于CTL-ACT与PAMPs的结合活性,同时两种蛋白与PAMPs和溶藻弧菌的结合活性具有浓度依赖性。结果表明三疣梭子蟹CTL基因参与机...

SNP SITE E4-205 C/T OF CTL GENE AND ITS ASSOCIATION WITH VIBRIO ALGINOLYTICUS RESISTANCE IN PORTUNUS TRITUBERCULATUS

C-type lectin (CTL) is one of the important immune factors in humoral immunity of crustaceans. However, the expression of the CTL gene and its anti-disease mechanism in Portunus trituberculatus infected by Vibrio alginolyticus are not clear. To understand the molecular mechanism against V. alginolyticus infection at the site of CTL gene SNP E4-205 C/T, different genotypes of P. trituberculatus were infected with V. alginolyticus and the replication of V. alginolyticus in hepatopancreas and muscle tissues of P. trituberculatus were analyzed by absolute quantitative method. Results show that the number of bacteria in group C/C in hepatopancreas and muscle tissues in 12 h after infection was significantly greater than that in group T/T. The anti-infection ability of P. trituberculatus in group T/T was significantly higher than that in group C/C. Furthermore, the two proteins of one amino acid change (Thr-Ile) caused by non-synonymous mutation (ACT-ATT) at this site were recombinantly expressed and purified in vitro, and the activities of the two recombinant proteins CTL-ATT and CTL-ACT were analyzed. Results show that the two recombinant proteins inhibited the growth of V. alginolyticus, and the antibacterial activity of CTL-ATT was significantly higher than that of CTL-ACT. The binding activities of PAMPs and V. alginolyticus of recombinant protein CTL-ATT were higher than those of CTL-ACT, and those of two proteins to PAMPs and V. alginolyticus were concentration-dependent. This study indicate that the CTL gene of P. trituberculatus was involved in the immune response process after being infected by V. alginolyticus, and its polymorphism had a certain correlation with anti-V. alginolyticus infection. When the site of SNP E4-205 of the CTL gene was the T/T genotype, the anti-V. alginolyticus infection ability of P. trituberculatus was higher than that of C/C type.