Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China.
Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, 116023, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, 116023, China.
Fish Shellfish Immunol. 2023 Jul;138:108829. doi: 10.1016/j.fsi.2023.108829. Epub 2023 May 16.
Mannose-binding lectin-associated serine protease (MASP) is a type of central serine protease in the complement lectin pathway. In the present study, a MASP-like was identified from the Pacific oyster Crassostrea gigas, defined as CgMASPL-2. The cDNA sequence of CgMASPL-2 was of 3399 bp with an open reading frame of 2757 bp and encoded a polypeptide of 918 amino acids containing three CUB domains, an EGF domain, two IG domains, and a Tryp_SPC domain. In the phylogenetic tree, CgMASPL-2 was firstly clustered with Mytilus californianus McMASP-2-like, and then assigned into the invertebrate branch. CgMASPL-2 shared similar domains with M. californianus McMASP-2-like and Littorina littorea LlMReM1. CgMASPL-2 mRNA was expressed in all the tested tissues with the highest expression in haemolymph. CgMASPL-2 protein was mainly distributed in the cytoplasm of haemocytes. The mRNA expression of CgMASPL-2 increased significantly in haemocytes after Vibrio splendidus stimulation. The recombinant 3 × CUB-EGF domains of CgMASPL-2 displayed binding activities to diverse polysaccharides (lipopolysaccharide, peptidoglycan and mannose) and microbes (Staphylococcus aureus, Micrococcus luteus, Pichia pastoris, Vibrio anguillarum, V. splendidus and Escherichia coli). In anti-CgMASPL-2 treated oysters, the mRNA expressions of CgIL17-1 and CgIL17-2 in haemocytes decreased significantly after V. splendidus stimulation. The results indicated that CgMASPL-2 could directly sense microbes and regulate the mRNA expressions of inflammatory factors.
甘露糖结合凝集素相关丝氨酸蛋白酶（MASP）是补体凝集素途径中的一种中心丝氨酸蛋白酶。本研究从太平洋牡蛎（Crassostrea gigas）中鉴定出一种 MASP 样蛋白，命名为 CgMASPL-2。CgMASPL-2 的 cDNA 序列长 3399bp，开放阅读框长 2757bp，编码一个 918 个氨基酸的多肽，包含三个 CUB 结构域、一个 EGF 结构域、两个 IG 结构域和一个 Tryp_SPC 结构域。在系统进化树中，CgMASPL-2 首先与加利福尼亚贻贝（Mytilus californianus）McMASP-2 样蛋白聚类，然后归属于无脊椎动物分支。CgMASPL-2 与加利福尼亚贻贝 McMASP-2 样蛋白和紫贻贝（Littorina littorea）LlMReM1 具有相似的结构域。CgMASPL-2 mRNA 在所有检测的组织中均有表达，在血淋巴中表达量最高。CgMASPL-2 蛋白主要分布在血细胞的细胞质中。在受到灿烂弧菌刺激后，血淋巴细胞中 CgMASPL-2 的 mRNA 表达显著增加。CgMASPL-2 的 3×CUB-EGF 结构域重组蛋白与多种多糖（脂多糖、肽聚糖和甘露糖）和微生物（金黄色葡萄球菌、藤黄微球菌、巴斯德毕赤酵母、鳗弧菌、灿烂弧菌和大肠杆菌）具有结合活性。在抗 CgMASPL-2 处理的牡蛎中，在受到灿烂弧菌刺激后，血淋巴细胞中 CgIL17-1 和 CgIL17-2 的 mRNA 表达显著下降。结果表明，CgMASPL-2 可以直接感知微生物，并调节炎症因子的 mRNA 表达。
