Faculty of Life Science and Biotechnology, Ningbo University, Ningbo 315211, People's Republic of China.
Fish Shellfish Immunol. 2011 Jul;31(1):52-7. doi: 10.1016/j.fsi.2011.03.005. Epub 2011 Mar 17.
Cathelicidins, one family of antimicrobial peptides, play important roles against infections in animals. In this study, a cDNA sequence coding for cathelicidin was cloned from constructed liver cDNA library of ayu, Plecoglossus altivelis. The deduced ayu cathelicidin (aCATH) has a 20 amino acid residue signal peptide, a conserved cathelin domain of 110 amino acid residues and a mature antimicrobial peptide of 61 amino acid residues. Sequence comparison and phylogenetic tree analysis confirmed aCATH as a distinct member of fish cathelicidins. Real-time quantitative PCR revealed that the aCATH transcripts dramatically increased in various tissues after bacterial infection. Subsequently, aCATH was prokaryotic expressed and purified. Western blot and mass spectrometry revealed that aCATH was cleaved at residue Ile130-Arg131 by human neutrophil elastase to release the mature antimicrobial peptide. The mature peptide of aCATH was chemically synthesized and exhibited potent antimicrobial activity. Thus, aCATH may play an important role in the innate immunity of ayu, and this work enriches our knowledge in fish antimicrobial peptides.
鱼抗菌肽 cathelicidins，作为一类抗微生物肽，在动物抗感染中发挥着重要作用。本研究从牙鲆肝脏 cDNA 文库中克隆到一个编码 cathelicidin 的 cDNA 序列。推导出的牙鲆抗菌肽 (aCATH) 具有 20 个氨基酸残基的信号肽、110 个氨基酸残基的保守 cathelin 结构域和 61 个氨基酸残基的成熟抗菌肽。序列比较和系统进化树分析证实 aCATH 是鱼类 cathelicidins 的一个独特成员。实时定量 PCR 显示，细菌感染后各种组织中 aCATH 转录本显著增加。随后，原核表达并纯化了 aCATH。Western blot 和质谱分析表明，aCATH 被人中性粒细胞弹性蛋白酶在残基 Ile130-Arg131 处切割，释放成熟的抗菌肽。化学合成的 aCATH 成熟肽表现出强大的抗菌活性。因此，aCATH 可能在牙鲆的先天免疫中发挥重要作用，本研究丰富了我们对鱼类抗菌肽的认识。
