Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 510300, Guangzhou, Guangdong Province, China.
Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 510300, Guangzhou, Guangdong Province, China; Sanya Tropical Fisheries Research Institute, Sanya, 572018, China; Guangdong Provincial Engineer Technology Research Center of Marine Biological Seed Industry, Guangzhou, Guangdong Province, China.
Fish Shellfish Immunol. 2024 Oct;153:109860. doi: 10.1016/j.fsi.2024.109860. Epub 2024 Aug 28.
In addition to controlling gene expression, mediating DNA folding into chromatin, and responding to immunological stimuli, histones are also thought to have antimicrobial effects. This study identified the molecular characteristics of core Histone MacroH2A2 (TOMacroH2A2) and Histone H2B 1/2 (TOH2B) from Trachinotus ovatus, and the antimicrobial potential of their derived peptides (To.mh2a and To. h2b). The open reading frames (ORFs) of TOMacroH2A2 and TOH2B from T. ovatus were 1010 bp and 375 bp, encoding polypeptides of 369 and 124 amino acids, respectively. The TOMacroH2A2 included an H2A domain and an A1pp domain, while TOH2B included an H2B domain. The amino acid sequences of TOMacroH2A2 and TOH2B demonstrated high homology with other teleost's sequences of histone macroh2a2 and histone h2b, with homologies exceeding 90 %. Expression analysis showed high expression of TOMacroH2A2 in brain, stomach, heart, and skin tissues and TOH2B in gill, brain, and skin tissues. In addition, the histone-derived peptides To. mh2a and To. h2b, synthesized based on two histone sequences from T. ovatus, exhibited typical physical characteristics of antimicrobial peptides, including positive charges, amphipathicity, hydrophobicity, and rich α-helix structure. Crucially, the vitro antibacterial results demonstrated that To. mh2a and To. h2b can inhibit the growth of various aquatic pathogens including Streptococcus agalactiae, Staphylococcus aureus, Bacillus subtilis, Acinetobacter baumannii, Aeromonas hydrophila, and Escherichia coli to varying degrees. Specifically, To. mh2a and To. h2b were capable of disrupting the cell surface structures of S. aureus and penetrating the cell membrane, leading to the leakage of cellular contents, thereby exerting their antibacterial effects. Furthermore, gel electrophoresis migration assays showed that To. mh2a and To. h2b participated in antimicrobial activity by binding to bacterial genomic DNA and reducing the migration rate of gDNA in a dose-dependent manner. The minimum effective concentration for binding to DNA was approximately 50 μM. In conclusion, our study suggested that To. mh2a and To. h2b can act as antimicrobial peptides, providing a potential strategy for controlling bacterial diseases in T. ovatus.
除了控制基因表达、介导 DNA 折叠成染色质以及响应免疫刺激外，组蛋白还被认为具有抗菌作用。本研究鉴定了卵形鲳鲹核心组蛋白 MacroH2A2（TOMacroH2A2）和组蛋白 H2B1/2（TOH2B）的分子特征，并研究了其衍生肽（To.mh2a 和 To. h2b）的抗菌潜力。卵形鲳鲹 TOMacroH2A2 和 TOH2B 的开放阅读框（ORF）分别为 1010bp 和 375bp，分别编码 369 和 124 个氨基酸的多肽。TOMacroH2A2 包含 H2A 结构域和 A1pp 结构域，而 TOH2B 包含 H2B 结构域。TOMacroH2A2 和 TOH2B 的氨基酸序列与其他硬骨鱼的组蛋白 macroh2a2 和组蛋白 h2b 序列具有高度同源性，同源性超过 90%。表达分析表明，TOMacroH2A2 在脑、胃、心脏和皮肤组织中高表达，TOH2B 在鳃、脑和皮肤组织中高表达。此外，根据卵形鲳鲹的两个组蛋白序列合成的组蛋白衍生肽 To. mh2a 和 To. h2b 表现出典型的抗菌肽物理特性，包括正电荷、两亲性、疏水性和富含α-螺旋结构。重要的是，体外抗菌结果表明，To. mh2a 和 To. h2b 可以不同程度地抑制包括无乳链球菌、金黄色葡萄球菌、枯草芽孢杆菌、鲍曼不动杆菌、嗜水气单胞菌和大肠杆菌在内的各种水产病原菌的生长。具体而言，To. mh2a 和 To. h2b 能够破坏金黄色葡萄球菌的细胞表面结构并穿透细胞膜，导致细胞内容物泄漏，从而发挥其抗菌作用。此外，凝胶电泳迁移分析表明，To. mh2a 和 To. h2b 通过与细菌基因组 DNA 结合并以剂量依赖的方式降低 gDNA 的迁移率来参与抗菌活性。与 DNA 结合的最小有效浓度约为 50μM。综上所述，本研究表明 To. mh2a 和 To. h2b 可以作为抗菌肽，为卵形鲳鲹细菌性疾病的防治提供了一种潜在策略。
