Gan Zhen, Chen Shannan, Hou Jing, Huo Huijun, Zhang Xiaolin, Ruan Baiye, Laghari Zubair Ahmed, Li Li, Lu Yishan, Nie Pin
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; College of Fishery, Guangdong Ocean University, Zhanjiang 524025, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Fish Shellfish Immunol. 2016 Jul;54:1-10. doi: 10.1016/j.fsi.2016.03.158. Epub 2016 Mar 28.
PGRP-SC2, the member of PGRP family, plays an important role in regulation of innate immune response. In this paper, a PGRP-SC2 gene of Nile tilapia, Oreochromis niloticus (designated as On-PGRP-SC2) was cloned and its expression pattern under the infection of Streptococcus agalactiae was investigated. Sequence analysis showed main structural features required for amidase activity were detected in the deduced amino acid sequence of On-PGRP-SC2. In healthy tilapia, the On-PGRP-SC2 transcripts could be detected in all the examined tissues, with the most abundant expression in the muscle. When infected with S. agalactiae, there was a clear time-dependent expression pattern of On-PGRP-SC2 in the spleen, head kidney and brain. The assays for the amidase activity suggested that recombinant On-PGRP-SC2 protein had a Zn(2+)-dependent PGN-degrading activity. Moreover, our works showed that recombinant On-PGRP-SC2 protein could significantly reduce bacterial load in target organs attacked by S. agalactiae. These findings indicated that On-PGRP-SC2 may play important roles in the immune response to S. agalactiae in Nile tilapia.
PGRP - SC2是PGRP家族成员，在先天免疫反应的调节中发挥重要作用。本文克隆了尼罗罗非鱼（Oreochromis niloticus）的PGRP - SC2基因（命名为On - PGRP - SC2），并研究了其在无乳链球菌感染下的表达模式。序列分析表明，在On - PGRP - SC2推导的氨基酸序列中检测到了酰胺酶活性所需的主要结构特征。在健康罗非鱼中，可在所有检测组织中检测到On - PGRP - SC2转录本，在肌肉中表达最为丰富。当感染无乳链球菌时，On - PGRP - SC2在脾脏、头肾和脑中呈现明显的时间依赖性表达模式。酰胺酶活性测定表明，重组On - PGRP - SC2蛋白具有锌（2 +）依赖性的肽聚糖降解活性。此外，我们的研究表明，重组On - PGRP - SC2蛋白可显著降低无乳链球菌攻击的靶器官中的细菌载量。这些发现表明，On - PGRP - SC2可能在尼罗罗非鱼对无乳链球菌的免疫反应中发挥重要作用。
