A lysin motif-containing protein (SpLysMD3) functions as a PRR involved in the antibacterial responses of mud crab, Scylla paramamosain
A lysin motif-containing protein (SpLysMD3) functions as a PRR involved in the antibacterial responses of mud crab, Scylla paramamosain
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含有溶素基序的蛋白 (SpLysMD3) 作为 PRR 参与青蟹 (Scylla paramamosain) 的抗菌反应
DOI：
10.1016/j.fsi.2019.12.036
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发表时间：
2020
影响因子：
4.7
通讯作者：
Ma Hongyu
中科院分区：
文献类型：
--
作者：
Wang Yue;Wang Xue-Peng;Zhang Bin;Li Zhi-Min;Yang Li-Guo;Li Xin-Cang;Ma Hongyu
赖氨酸基序（LysM）蛋白在植物中作为模式识别受体，识别不同的N-乙酰葡萄糖胺配体，从而引发植物对病原菌的特异性防御反应。然而，这些蛋白质在动物中的生物学功能仍不清楚。在本研究中，我们鉴定了拟穴青蟹中一种新的LysM蛋白，命名为SpLysMD 3。SpLysMD 3的cDNA序列长1058 bp，开放阅读框长840 bp，编码279个氨基酸残基。SpLysMD 3在鳃、肠、肌肉和血细胞中高表达，且在细菌攻击后表达上调，可能参与抗菌防御。结合试验表明，SpLysMD 3对所有供试微生物以及细菌细胞壁组分脂多糖（LPS）和肽聚糖（PGN）都具有特异性结合活性，表明SpLysMD 3是梭子蟹中重要的LPS和PGN结合蛋白。细菌清除实验表明，SpLysMD 3包被细菌可加速细菌清除。通过使用SpLysMD 3沉默的螃蟹注射S.金黄色的;副溶血性SilencingSpLysMD 3显著抑制细菌清除。同时，SpLysMD 3的敲低也严重影响了一组特定抗菌肽（AMP）的表达;此外，SpLysMD 3的过表达可以增强SpALF 2的启动子活性。这些结果表明SpLysMD 3通过调节AMP影响细菌清除。综上所述，SpLysMD 3可能作为一种潜在的受体参与天然免疫，通过与LPS和PGN结合，调节AMP清除入侵的病原体。该研究为了解LysM蛋白在动物体内的生物学功能和甲壳动物抗菌活性的机制提供了新的见解。
Lysin motif (LysM)-containing proteins function as pattern-recognition receptors in plants to recognize differentN-acetylglucosamine-containing ligands, thereby triggering specific defense responses against pathogens. However, the biological functions of these proteins in animals remain unclear. In this study, we characterized a novel LysM protein, designated asSpLysMD3, in mud crabScylla paramamosain. The cDNA sequence ofSpLysMD3had 1058 bp with an open reading frame of 840 bp encoding a protein with 279 amino acid residues. The deduced protein contained a LysM domain and a transmembrane region.SpLysMD3was highly expressed in gills, intestine, muscle, and hemocytes and upregulated after challenges with bacteria, suggesting that it may be involved in antibacterial defense. Binding assay showed thatSpLysMD3 possessed specific binding activities to all tested microorganisms as well as bacterial cell wall components lipopolysaccharide (LPS) and peptidoglycan (PGN), indicating thatSpLysMD3 was an important LPS- and PGN-binding protein in mud crab. Bacterial clearance assay revealed that coating bacteria withSpLysMD3 accelerated bacterial clearancein vivo. The promotion of bacterial clearance bySpLysMD3 was further determined by usingSpLysMD3-silenced crabs injected withS. aureusorV. parahemolyticus. SilencingSpLysMD3dramatically suppressed the bacterial clearance. Meanwhile, knockdown ofSpLysMD3also severely impaired the expression of a specific set of antimicrobial peptides (AMPs); moreover,SpLysMD3 overexpression can enhance the promoter activity ofSpALF2. These results suggested thatSpLysMD3affected bacterial clearance by regulating AMPs. Collectively, all the results demonstrated thatSpLysMD3 may function as a potential receptor involved in innate immunity by binding to LPS and PGN and by regulating AMPs to eliminate invading pathogen. This study provided new insights into the biological functions of LysM proteins in animals and the mechanisms underlying the antibacterial activity of crustaceans.