title: The first invertebrate RIG-I-like receptor (RLR) homolog gene in the pacific oyster Crassostrea gigas.
abstract: Retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) is a pivotal receptor that detects numerous RNA and DNA viruses and mediates the innate induction of interferons and pro-inflammatory cytokines upon viral infection. In the present study, we cloned and characterized the first RIG-I gene in a marine mollusk, Crassostrea gigas, and designated it as CgRIG-I. The full-length CgRIG-I cDNA is 3436 bp, including 5'- and 3'-untranslated regions (UTRs) of 93 bp and 286 bp, respectively, and an open reading frame (ORF) of 3057 bp. The gene encodes a 1018 amino acid polypeptide with an estimated molecular mass of 116.5 kDa. SMART analysis showed that the CgRIG-I protein had the typical conserved domains, including the caspase activation and recruitment domains (CARDs), the RNA helicase domain and the C-terminal regulatory domain (RD). Phylogenetic analysis revealed that CgRIG-I was grouped into the clade of its vertebrate homologs. Moreover, CgRIG-I expression could be specifically increased after stimulation by poly(I:C) rather than by other PAMPs such as lipopolysaccharide (LPS), peptidoglycan (PGN), heat-killed Listeria monocytogenes (HKLM) and heat-killed Vibrio alginolyticus (HKVA). Meanwhile, six IRF, three STAT and one NF-κB predicted sites were identified in the CgRIG-I promoter, which was consistent with its high responsiveness to poly(I:C). In summary, this report provides the first CgRIG-I sequence of a mollusk, but its function in the antiviral immune response requires further investigation.
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yu
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Yuehuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. Electronic address: carlzyu@scsio.ac.cn.
authors.forename: Ziniu
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000276:immunology; D003001:Cloning, Molecular; D049896:Crassostrea / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D016415:Sequence Alignment
chemical_list: D000276:Adjuvants, Immunologic; D011135:Polysaccharides, Bacterial; D053487:DEAD-box RNA Helicases; D011070:Poly I-C
keywords: Antiviral immune response; Crassostrea gigas; PAMP challenge; Retinoic acid-inducible gene I