RING domain is essential for the antiviral activity of TRIM25 from orange spotted grouper.
Tripartite motif-containing 25 (TRIM25) has been demonstrated to exert crucial roles in the regulation of innate immune signaling. However, the roles of fish TRIM25 in antiviral immune response still remained uncertain. Here, a novel fish TRIM25 gene from orange spotted grouper (EcTRIM25) was cloned and its roles in grouper virus infection were elucidated. EcTRIM25 encoded a 734-aa protein which shared 68% identity to large yellow croaker (Larimichthys crocea). Amino acid alignment showed that EcTRIM25 contained three conserved domains, including a RING-finger domain, a B box/coiled-coil domain and a SPRY domain. In healthy grouper, the transcript of EcTRIM25 was predominantly detected in skin, spleen and intestine. After stimulation with Singapore grouper iridovirus (SGIV) or poly I:C, the relative expression of EcTRIM25 in grouper spleen was significantly increased at the early stage of injection. Subcellular localization analysis showed that EcTRIM25 distributed throughout the cytoplasm in grouper cells. Notably, the deletion RING domain affected its accurate localization and displayed microtubule like structures or bright aggregates in GS cells. After incubation with SGIV or red spotted grouper nervous necrosis virus (RGNNV), overexpression of full length of EcTRIM25 in vitro significantly decreased the viral gene transcription of SGIV and RGNNV. Consistently, the deletion of RING domain obviously affected the inhibitory effect of EcTRIM25. Furthermore, overexpression of EcTRIM25 significantly increased the expression level of interferon related signaling molecules, including interferon regulatory factor (IRF) 3, interferon-induced 35-kDa protein (IFP35), MXI, IRF7 and myeloid differentiation factor 88 (MyD88), suggesting that the positive regulation of interferon immune response by EcTRIM25 might affected RGNNV replication directly. Meanwhile, the expression levels of pro-inflammation cytokines were differently regulated by the ectopic expression of EcTRIM25. We proposed that the regulation of IRF7, MyD88 and pro-inflammation cytokines might contribute more important roles in SGIV infection. In addition, the RING domain of EcTRIM25 also played critical roles in the regulation of interferon immune and inflammation response. Together, our results will provide new evidences that the RING domain was essential for the antiviral action of fish TRIM25 against iridovirus and nodavirus infection.
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China.
Ying
Y
Yang
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China.
Youhua
Y
Huang
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China.
Yepin
Y
Yu
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China.
Min
M
Yang
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China.
Sheng
S
Zhou
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: qinqw@scsio.ac.cn.
Qiwei
Q
Qin
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: huangxh@scsio.ac.cn.
Xiaohong
X
Huang
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001492:Bass; D003001:Cloning, Molecular; D004266:DNA Virus Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000821:virology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017995:Ranavirus / Q000502:physiology; D016415:Sequence Alignment / Q000662:veterinary; D000070584:Tripartite Motif Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D000276:Adjuvants, Immunologic; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D000070584:Tripartite Motif Proteins; D011070:Poly I-C
Grouper; Iridovirus; RGNNV; RING domain; TRIM25