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Characterization of p38 MAPKs from orange-spotted grouper, Epinephelus coioides involved in SGIV infection

Cai, Jia, Huang, Youhua, Wei, Shina, Huang, Xiaohong, Ye, Fuzhou, Fu, Jing, Qin, Qiwei
Fish & shellfish immunology 2011 v.31 no.6 pp. 1129-1136
Epinephelus coioides, Singapore grouper iridovirus, apoptosis, binding sites, gene overexpression, genes, grouper, kidneys, mammals, mitogen-activated protein kinase, phylogeny, protein synthesis, tissue distribution, transcription (genetics), virus replication
p38 mitogen-activated protein kinases (MAPKs) are broadly expressed signaling molecules that involves in the regulation of cellular responsible for various extracellular stimuli. In this study, three p38 MAPK genes (Ec-p38a, p38b and p38β) were cloned from grouper, Epinephelus coioides and their characteristics were investigated in vitro. Although Ec-p38a, p38b and p38β showed high homologies to other fish p38a MPAK, p38b MAPK and p38β MAPK, respectively, they all contained the conserved structures of Thr-Gly-Tyr (TGY) motif and substrate binding site Ala-Thr-Arg-Trp (ATRW). Phylogenetic analysis indicated that Ec-p38a, p38b and p38β are more closely related to those from fish than mammals. The tissue distribution patterns of Ec-p38a, p38b and p38β were different, and Ec-p38β was up-regulated most obviously in head kidney after Singapore grouper iridovirus (SGIV) infection. Overexpression of Ec-p38β in FHM cells delayed the occurrence of CPE induced by SGIV infection. Further analysis indicated that overexpression of Ec-p38β inhibited viral gene transcription and protein synthesis, as well as SGIV induced typical apoptosis in fish cells. Taken together, our data indicated that Ec-p38β played a crucial role in regulating apoptosis and virus replication during iridovirus infection.