克隆并鉴定墨吉明对虾(Fenneropenaeus merguiensis)的一种c型溶菌酶基因(Fm-Lyz),其cDNA全长为770 bp,包括71 bp的5′ 非编码区(UTR)、222 bp的3′UTR和477 bp完整开放阅读框,编码158个氨基酸.SMART分析显示,Fm-Lyz氨基酸序列包含1个LYZ1结构域和1个含18个氨基酸的信号肽.同源性分析发现,Fm-Lyz与斑节对虾(Penaeus monodon)溶菌酶同源性最高;进化树结果显示,Fm-Lyz与不同对虾的c型溶菌酶聚为一类.实时荧光定量PCR结果显示,Fm-Lyz在所测组织中均有表达,其中在血细胞中表达量最高.副溶血弧菌(Vibrio parahaemolyticus)和溶壁微球菌(Micrococcus lysodeikticus)感染后,Fm-Lyz表达量比对照组明显上调(P﹤0.05),最高表达量时间分别为感染后24、12 h,暗示Fm-Lyz参与了墨吉明对虾的抗菌免疫防御.%The gene of a c-type lysozyme, namely Fm-lyz, from Fenneropenaeus merguiensis was cloned and identified. The full-length cDNA of Fm-Lyz is 770 bp with 5' UTR of 71 bp, 3' UTR of 222 bp and an open reading frame(ORF) of 477 bp, which encodes a putative protein of 158 amino acids including a LYZ1 domain and a signal peptide with 18 amino acids. Multiple alignment analysis shows that Fm-Lyz shares the highest amino acid identity with Penaeus monodon. Phylogenetic analysis shows that Fm-Lyz is clustered into c-type lysozyme group of shrimp. qPCR analysis shows that Fm-Lyz is constitutively expressed in all the examined tissues with the highest expression in hemolymph. Upon Vibrio parahaemolyticus and Micrococcus lysodeikticus challenge, the expression of Fm-Lyz is significantly up-regulated compared with the control group (PBS group), and the time points of the highest expression is 24 h and 12 h, respectively, which suggests that Fm-Lyz may involve in anti-bacterial host defense.
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