School of Agriculture, Ludong University, Yantai, 264025, China.
School of Resources and Environmental Engineering, Ludong University, Yantai, 264025, China.
Fish Shellfish Immunol. 2022 Sep;128:238-245. doi: 10.1016/j.fsi.2022.08.005. Epub 2022 Aug 6.
The LGP2 (Laboratory of Genetics and Physiology 2) protein is a member of the retinoic acid-inducible gene I (RIG-I)-like receptor (RLRs) family, which is a class of antiviral pattern recognition receptors located in the cytoplasm. However, few studies have investigated the function of LGP2 in invertebrates. In this study, the complete coding sequence of the LGP2 gene of the Pacific oyster, Crassostrea gigas, was obtained and named CgLGP2-like. Sequence analysis revealed that CgLGP2-like encodes 803 amino acids, and the encoded protein contains a DEXDc, HELICc, and C-terminal regulatory domains. Multiple sequence alignment demonstrated that the sequences of these key protein functional domains were relatively conserved. Phylogenetic analysis revealed that CgLGP2-like was a new member of the animal LGP2 family. Quantitative real-time PCR results showed that CgLGP2-like mRNA was expressed in all tested oyster tissues, with the highest expression observed in the labial palpus and digestive glands. CgLGP2-like expression in gill tissues was significantly induced after the poly(I:C) challenge. Furthermore, multiple IRF and NF-κB binding sites were identified in the CgLGP2-like promoter region, which may be one of the reasons why CgLGP2-like responds to poly(I:C) stimulation. Finally, the results of dual-luciferase reporter gene assays revealed that overexpression of CgLGP2-like may have a regulatory effect on the human IFN, AP-1, and oyster CgIL-17 genes in HEK293T cells. Overall, our results preliminarily elucidate the immune functions of invertebrate LGP2 protein and provide valuable information for the development of comparative immunology.
LGP2（遗传学和生理学实验室 2）蛋白是维甲酸诱导基因 I（RIG-I）样受体（RLRs）家族的成员，该家族是一类位于细胞质中的抗病毒模式识别受体。然而，很少有研究调查 LGP2 在无脊椎动物中的功能。在本研究中，获得了太平洋牡蛎 Crassostrea gigas 的 LGP2 基因的完整编码序列，并将其命名为 CgLGP2-like。序列分析表明，CgLGP2-like 编码 803 个氨基酸，编码蛋白含有 DEXDc、HELICc 和 C 端调节结构域。多重序列比对表明，这些关键蛋白功能结构域的序列相对保守。系统进化分析表明，CgLGP2-like 是动物 LGP2 家族的一个新成员。定量实时 PCR 结果表明，CgLGP2-like mRNA 在所有测试的牡蛎组织中均有表达，在唇瓣和消化腺中表达最高。在鳃组织中，CgLGP2-like 的表达在 poly(I:C) 挑战后显著诱导。此外，在 CgLGP2-like 启动子区域鉴定出多个 IRF 和 NF-κB 结合位点，这可能是 CgLGP2-like 对 poly(I:C)刺激产生反应的原因之一。最后，双荧光素酶报告基因检测结果表明，CgLGP2-like 的过表达可能对 HEK293T 细胞中的人 IFN、AP-1 和牡蛎 CgIL-17 基因具有调节作用。总之，我们的结果初步阐明了无脊椎动物 LGP2 蛋白的免疫功能，并为比较免疫学的发展提供了有价值的信息。
