文献类型：期刊文献

英文题名：Molecular cloning and characterization of a new G-type lysozyme gene (Ec-lysG) in orange-spotted grouper, Epinephelus coioides

作者：Wei, Shina[1];Huang, Youhua[1];Huang, Xiaohong[1];Cai, Jia[1,2];Wei, Jingguang[1];Li, Pengfei[1,3];Ouyang, Zhengliang[1];Qin, Qiwei[1]

机构：[1]Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Trop Marine Bioresources & Ecol, Guangzhou 510301, Guangdong, Peoples R China;[2]Guangdong Ocean Univ, Coll Fishery, Zhanjiang 524088, Peoples R China;[3]Univ Chinese Acad Sci, Beijing 100049, Peoples R China

年份：2014

卷号：46

期号：2

起止页码：401

外文期刊名：DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY

收录：SCI-EXPANDED(收录号：WOS:000340216600031)、、WOS

基金：We thank Professor Li Anxing from Sun Yat-sen University for supplying Streptococcus iniae strains. This work was supported by grants from National Basic Research Program of China (973) (2012CB114402), National High Technology Development Program of China (863) (2014AA093507, 2012AA092201) and Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11020203).

语种：英文

外文关键词：Epinephelus coioides; G-type lysozyme; Antimicrobial activity; Innate immunity

外文摘要：Lysozyme acts as an innate immunity molecule against pathogen infection. In this study, a new G-type lysozyme gene with a typical G-type lysozyme domain (designated as Ec-lysG) was cloned and characterized from the orange-spotted grouper, Epinephelus coioides. The full-length Ec-lysG cDNA contains 1419 bp and encodes a 256-residue protein containing a 25-residue signal peptide at the N-terminus. BLAST analysis reveals Ec-lysG shares 64% identity with Siniperca chuatsi, but 63% to another reported G-type lysozyme from orange-spotted grouper (OSG-lysG). The genomic DNA of Ec-lysG contains four exons and three introns, with a total length of 2062 bp. An amino acid sequence alignment showed that Ec-lysG shares the fundamental structural features of G-type lysozyme, including the catalytic residues, substrate binding sites, and soluble lytic transglycosylase domain. Quantitative PCR showed that Ec-lysG transcript is most abundant in the head kidney, and less abundant in the heart. The expression of Ec-lysG was differentially upregulated in the head kidney after stimulation with lipopolysaccharide, Vibrio alginolyticus, and Singapore grouper iridovirus (SGIV). A subcellular localization analysis showed that Ec-lysG is distributed predominantly in the cytoplasm. Recombinant Ec-lysG (rEc-lysG) has optimal activity at pH 7.5 and 35 degrees C. rEc-lysG showed lytic activities against Gram-positive bacterium Streptococcus iniae, Staphylococcus aureus, and Micrococcus lysodeikticus, and the Gram-negative bacterium V. alginolyticus. Scanning electron microscopy (SEM) showed that rEc-lysG acts on M. lysodeikticus cell walls. The overexpression of Ec-lysG in grouper cells did not significantly delay the occurrence of the cytopathic effect (CPE) induced by SGIV, and did not inhibit viral gene transcription. In conclusion, Ec-lysG might be a potent antibacterial protein, with a role in innate immunity. (C) 2014 Elsevier Ltd. All rights reserved.