Molecular cloning and characterization of a cDNA encoding extracellular signal-regulated kinase from Litopenaeus vannamei.

Extracellular signal-regulated kinase (ERK) is a serine/threonine-specific kinase, which is activated by downstream signaling molecules of cellular activation, cytokine and chemokine stimulation and various other stimuli. Here we cloned an ERK gene from Litopenaeus vannamei and designated it as lverk. The lverk cDNA contained an open reading frame of 1098 bp encoding 365 amino acids. LVERK had a conserved TEY motif and serine/threonine protein kinase (S_TKc) domain, and close phylogenetic relationship to Penaeus monodon and Marsupenaeus japonicus ERK. Immunofluorescence staining analysis showed that following serum stimulation LVERK was located in cytoplasm and nucleus, but phospho-LVERK was prominently in nucleus, suggesting conserved ERK signaling module occurred in shrimp cells. Then during the white spot syndrome virus (WSSV) infection, LVERK and phospho-LVERK increased at the early stage of infection. Once silencing of lverk in vivo, the replication of WSSV was obviously inhibited. Moreover, treatment of mitogen-activated protein kinase kinase inhibitor in vitro could result in reduction of WSSV proliferation and delay of viral early gene transcription. Our results indicated a role of LVERK involved in WSSV infection. Understanding how WSSV influences ERK signaling pathway to dismantle an effective immune response may lead to insight into pathogenic progression and possible disease control.

Shi H ，Yan X ，Xu X ，Ruan L ... -  《-》

Identification, cloning and characterization of an extracellular signal-regulated kinase (ERK) from Chinese shrimp, Fenneropenaeus chinensis.

Extracellular signal-regulated kinase (ERK) is a serine/threonine-specific protein kinase, which participates in signaling transduction pathways that control intracellular events, including resumption of meiosis, embryogenesis, cell differentiation, cell proliferation, cell death and response to radiation. Some virus species evolved the ability to hijack the host cell ERK signaling transduction pathway for viral replications and gene expressions. To obtain a better understanding of ERK, we cloned a cDNA encoding ERK from the muscle of Fenneropenaeus chinensis (FcERK). The FcERK contained a 1098 bp open reading frame (ORF) encoding a protein of 365 amino acid residues with a conserved phosphorylation motif TEY in the kinase activation loop. Pair-wise and multiple sequence alignment revealed that ERK is highly conserved across taxa. The FcERK gene expressions in the hepatopancreas and gill were noticeably higher than the expression observed in the muscle. A challenge test was performed to reveal the responses of FcERK in different tissues to white spot syndrome virus (WSSV) infection. Post WSSV challenge, the FcERK expression in the gill significantly increased during the early stage of the viral infection, the FcERK expression in the muscle increased later than that in the gill, and the FcERK expression in the hepatopancreas significantly decreased. The FcERK gene expression profile accorded with the results that the virus primarily infects tissues originating from the ectoderm, with less infection of the tissues originating from the mesoderm, and hardly any infection in the tissues originating from the entoderm. Two single nucleotide polymorphisms (SNPs) were identified in the FcERK gene, involving C/T transition. The SNP genotypes of two groups of shrimps, respectively comprising 96 WSSV-resistant shrimps and 96 WSSV-susceptible shrimps were obtained using a high-resolution melting (HRM) method. In the two groups, the MAFs of both sites were greater than 0.05, and no site departed significantly (P < 0.05) from HWE. The genotype distributions of both mutation sites between the two groups were not significantly different. These results lead to a better understanding of the molecular mechanisms of the host-virus interaction and provide useful information for disease control.

Li X ，Meng X ，Kong J ，Luo K ，Luan S ，Cao B ，Liu N ，Pang J ，Shi X ... -  《-》

Cloning and characterization of a caspase gene from black tiger shrimp (Penaeus monodon)-infected with white spot syndrome virus (WSSV).

Wongprasert K ，Sangsuriya P ，Phongdara A ，Senapin S ... -  《JOURNAL OF BIOTECHNOLOGY》

A novel JNK from Litopenaeus vannamei involved in white spot syndrome virus infection.

The c-Jun N-terminal kinase (JNK), a member of MAP kinases, is a serine/threonine-specific protein kinase which responds to extracellular stimuli and regulate various cellular activities. It is well documented in innate immune responses and reported to be involved in various viral infections of mammals. In present study, we cloned JNK homolog in a crustacean, Litopenaeus vannamei (designated as LvJNK) and studied its role in white spot syndrome virus (WSSV) infection. Sequence analysis displayed that LvJNK shared high similarity with other members of the JNK subfamily, including the conserved TPY motif and serine/threonine protein kinase (S_TKc) domain. Western blot analysis showed that the activation of LvJNK took place in WSSV infection. LvJnk silencing mediated by specific dsRNA in shrimps could significantly inhibit the proliferation of the virus. Moreover, inhibition of shrimp JNK signaling pathway by specific inhibitor resulted in the reduction of WSSV replication and the delay of WSSV gene transcription. These results indicate for the first time that shrimp JNK is activated in response to WSSV infection and WSSV could benefit from JNK activation. It may facilitate our understanding of the molecular mechanism of virus infection and provided a potential target for preventing the WSSV infection.

Shi H ，Yan X ，Ruan L ，Xu X ... -  《-》

A thioredoxin response to the WSSV challenge on the Chinese white shrimp, Fenneropenaeus chinensis.

Ren Q ，Zhang RR ，Zhao XF ，Wang JX ... -  《COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY》