Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, China.
Dev Comp Immunol. 2010 May;34(5):553-61. doi: 10.1016/j.dci.2009.12.016. Epub 2010 Jan 6.
The superoxide dismutases (SODs) are a family of enzymes that function as the first line of antioxidant defense against highly reactive superoxide radicals. The bay scallop Argopecten irradians contains three unique superoxide dismutases: Ai-icCuZnSOD, Ai-MnSOD and Ai-ecCuZnSOD, which were characterized in our previous studies. qRT-PCR was also performed to characterize the temporal expression of SODs in the hemocytes of bay scallops injected with the bacterium Vibrio anguillarum. To characterize the SOD family in A. irradians completely, we evaluated the polymorphism in the SOD genes and investigated the association of this polymorphism with resistance/susceptibility to V. anguillarum. Fifty-nine SNPs were identified in the promoter, exon and partial intron sequences of the three SOD genes. AiECSOD contained the most SNPs, as compared to AiCuZnSOD and AiMnSOD, and the majority of these were located in the promoter. Among them, the genotypes of -1739 T-C SNP in the AiCuZnSOD promoter and alleles of the -498 A-T and -267 G-A SNPs in the AiECSOD promoter showed a significant association with resistance/susceptibility to V. angullarum (P<0.05). The only non-synonymous SNP that was identified, E1-38 C-A in Ai-ecCuZnSOD, was a dimorphism caused by a C to A transition that resulted in a Thr to Lys substitution at position 13 in the signal peptide. The Thr allele was associated with increased susceptibility to V. anguillarum (P<0.05). To confirm the presumption, another independent challenge experiment was performed, in which the cumulative mortality of Ai-icCuZnSOD Q-1739 genotype TT was significantly lower than TC (P<0.05). Ai-ecCuZnSOD Q-498 genotype AA and AT were significantly lower than TT (P<0.05), Ai-ecCuZnSOD E1-3 genotype AA was significantly higher than CA and CC (P<0.05). The results suggested that these three polymorphic loci could be potential gene markers for the future molecular selection of strains that are resistant to diseases caused by V. anguillarum.
超氧化物歧化酶（SODs）是一类酶，作为抗氧化防御的第一道防线，可抵抗高反应性的超氧自由基。海湾扇贝 Argopecten irradians 含有三种独特的超氧化物歧化酶：Ai-icCuZnSOD、Ai-MnSOD 和 Ai-ecCuZnSOD，这些酶在我们之前的研究中得到了表征。我们还通过 qRT-PCR 研究了细菌鳗弧菌注射海湾扇贝血细胞中 SODs 的时间表达特征。为了全面描述海湾扇贝的 SOD 家族，我们评估了 SOD 基因的多态性，并研究了这种多态性与对鳗弧菌的抗性/易感性的关联。在三个 SOD 基因的启动子、外显子和部分内含子序列中鉴定出 59 个 SNP。与 AiCuZnSOD 和 AiMnSOD 相比，AiECSOD 包含最多的 SNP，其中大多数位于启动子中。其中，AiCuZnSOD 启动子中的-1739 T-C SNP 基因型和 AiECSOD 启动子中的-498 A-T 和 -267 G-A SNPs 等位基因与对鳗弧菌的抗性/易感性呈显著关联（P<0.05）。唯一鉴定出的非同义 SNP 是 Ai-ecCuZnSOD 中的 E1-38 C-A，这是由 C 到 A 的转换引起的二态性，导致信号肽第 13 位的 Thr 突变为 Lys。Thr 等位基因与对鳗弧菌的易感性增加有关（P<0.05）。为了证实这一假设，进行了另一个独立的挑战实验，结果表明，Ai-icCuZnSOD Q-1739 基因型 TT 的累积死亡率明显低于 TC（P<0.05）。Ai-ecCuZnSOD Q-498 基因型 AA 和 AT 明显低于 TT（P<0.05），Ai-ecCuZnSOD E1-3 基因型 AA 明显高于 CA 和 CC（P<0.05）。结果表明，这三个多态性位点可能是未来鳗弧菌抗性菌株分子选择的潜在基因标记。
