title: Prostaglandin E receptor 4 (PTGER4) involved in host protection against immune challenge in oyster, Crassostrea hongkongensis.
abstract: Prostaglandin E receptor 4 (PTGER4) is an essential receptor that can detect various physiological and pathological stimuli and has been implicated in a wide variety of biological processes, including the regulation of immune responses, cytokine production, and apoptosis. In this report, the first mollusk PTGER4, referred to as ChPTGER4, was cloned and characterized from the Hong Kong oyster Crassostrea hongkongensis. Its full-length cDNA is 1734 bp in length, including 5'- and 3'-untranslated region (UTRs) of 354 bp and 306 bp, respectively, and an open reading frame (ORF) of 1074 bp. ChPTGER4 comprises 357 amino acids and shares significant homology with its vertebrate homologs. The results of phylogenetic analysis revealed that ChPTGER4 clusters with PTGER4 from the Pacific oyster. In addition, quantitative real-time PCR analysis revealed that ChPTGER4 was constitutively expressed in all tissues examined and that its expression was significantly up-regulated in hemocytes and gills following challenge by pathogens (Vibrio alginolyticus, Staphylococcus haemolyticus and Saccharomyces cerevisiae) and pathogen-associated molecular patterns (PAMPs: lipopolysaccharide (LPS) and peptidoglycan (PGN). Moreover, fluorescence microscopy analysis revealed that ChPTGER4 localized to the membrane, and its overexpression significantly enhanced NF-κB reporter gene activation in the HEK293T cell line. In summary, this study provides the first experimental evidence of a functional PTGER4 in mollusks, which suggests its involvement in the innate immune response in oyster.
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.
authors.forename: Fufa
authors.initials: F
authors.lastname: Qu
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Xiang
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.
authors.forename: Fuxuan
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Qi
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.
authors.forename: Fengjiao
authors.initials: F
authors.lastname: Xu
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China. Electronic address: carlzyu@scsio.ac.cn.
authors.forename: Ziniu
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D049896:Crassostrea / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000494:pharmacology; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011897:Random Allocation; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000502:physiology; D016415:Sequence Alignment; D041162:Staphylococcus haemolyticus / Q000502:physiology; D044149:Vibrio alginolyticus / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D008070:Lipopolysaccharides; D010457:Peptidoglycan; D012333:RNA, Messenger; D058309:Receptors, Prostaglandin E, EP4 Subtype
keywords: Crassostrea hongkongensis; Innate immunity; NF-κB pathway; Prostaglandin E receptor 4 (PTGER4)