抗菌肽是鱼类用于抵御外界微生物入侵的天然防御多肽,也是开发新型药物的重要先导分子.大弹涂鱼(Boleophthalmus pectinirostris)是一种特殊的可以营两栖生活的鱼类,其皮肤表面具有丰富的粘液,其中所含抗菌肽对其免疫防御和适应两栖生活具有重要意义.为深入了解大弹涂鱼皮肤组织基因表达谱并从中筛选抗菌肽相关基因,采用新一代Illumina高通量测序平台对大弹涂鱼皮肤组织进行了转录组测序.利用Trinity软件从头组装,从测得的78 608 366条双端测序读长(paired-end read)共计6GB的序列数据中获得119 848条高质量的蛋白质编码基因(unigene).经公共数据库序列检索和比对,发现7个unigene编码的多肽与已知的鱼类5大家族的抗菌肽高度同源,即β-防御素(β-defensin)、hepcidin、NK-lysin、piscidin和肝表达抗菌肽-2(liver-expressed antimicrobial peptide-2,LEAP-2).最后,对上述抗菌肽相关unigene开展了组织表达差异分析、序列比对及进化树分析.研究结果为进一步了解大弹涂鱼适应两栖生活的免疫防御机制和利用新鉴定的抗菌肽开发新型抗菌药物奠定了基础.%Antimicrobial peptides (AMPs) are employed by fish as the innate defense peptides to protect against the invasion of foreign microorganisms and are important lead molecules for the development of novel drugs.Boleophthalmus pectinirostris is a special fish that can live in amphibious environment;and the mucus from its skin is speculated to be rich in AMPs and has great significance to its immune defense and adaptation to the amphibious life.For understanding the gene expression patterns of B.pectinirostris skin and screening for antibacterial peptide related genes,the transcriptome analysis of the adult B.pectinirostris skin was performed by Illumina sequencing.A total of 78 608 366 paired-end reads amounting to 6 GB of sequence data were generated and further de novo assembled with Trinity software,yielding a total of 119 848 high-quality skin unigenes.When these unigenes were annotated in the available databases,7 unigenes were found to encode peptides homologous with the reported fish AMPs of 5 families with significant hits (E-value＜1.00E-05),i.e.β-defensin,hepcidin,NK-lysin,piscidin,and liver-expressed antimicrobial peptide-2(LEAP-2).Their differential expression in different tissues,sequence alignment and phylogenetic analysis were performed.The results provide a foundation for further understanding the immune defense mechanism for B.pectinirostris to adapt to the amphibious environment and developing novel antibiotics using the newly identified AMPs.
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