title: Molecular characterization and expression of a novel Toll gene from the swimming crab Portunus trituberculatus.
abstract: Tolls/Toll-like receptors (TLRs) are important cell-surface receptors serving as pattern recognition receptors (PRRs) in the Tolls/TLRs signaling pathway of innate immune responses. In the present study, we isolated and characterized a novel Toll gene (PtToll) from Portunus trituberculatus, and further investigated its expression in various tissues of crab hosts challenged with the parasitic dinoflagellate Hematodinium. The full-length cDNA of PtToll was 3745 bp, with a 3012 bp open reading frame (ORF) encoding 1003 amino acids. Conserved domains consist of 15 tandem leucine-rich repeats (LRRs), a single-pass transmembrane segment (TM) and a cytoplasmic Toll/interleukin-1R (TIR) domain. The PtToll protein shared high similarity to other crustacean Tolls and was clustered with the crustacean Tolls in the phylogenetic tree. The PtToll gene was constitutively expressed in various tissues of P. trituberculatus, with the highest expression in hemocytes. After being challenged with the parasite, the transcripts of PtToll reacted immediately with significant alterations in all the tested tissues, and decreased consistently in most of the detected tissues (e.g., hemocytes, gill, heart, and muscle) within 24h. Then the transcripts of PtToll were significantly up-regulated in hemocytes and heart at 48 h, and in hepatopancreas at 48 and 96 h post the parasitic challenge. By 192 h post challenge, the transcriptional level of PtToll indicated a significant suppression or a decreasing trend. The fluctuations of PtToll gene expression suggested that PtToll was closely associated with intrusion of the Hematodinium parasites, and may possess a vital and systematic function in the innate immunity of P. trituberculatus against the parasitic infection.
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: cwli@qdio.ac.cn.
authors.forename: Caiwen
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Shuqun
authors.initials: S
authors.lastname: Song
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003386:Brachyura / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010271:Parasites / Q000276:immunology; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013550:Swimming; D051193:Toll-Like Receptors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D051193:Toll-Like Receptors
keywords: Crustacean; Innate immunity; Parasite; Toll receptor; Transcript expression