title: A novel Toll like receptor with two TIR domains (HcToll-2) is involved in regulation of antimicrobial peptide gene expression of Hyriopsis cumingii.
abstract: Animal Toll-like receptors (TLRs) are involved in innate immunity. Toll proteins are generally transmembrane proteins. In this study, an atypical Toll-like receptor (HcToll-2) was identified from the triangle-shell pearl mussel Hyriopsis cumingii, which belongs to phylum Mollusca. Unlike the typical Toll like receptors with extracellular leucine-rich repeats (LRRs), transmembrane, and intracellular Toll/interleukin-1 receptor (TIR) domains, HcToll-2 has two homologous TIR domains located at the C-terminal (designated as HcTIR1 and HcTIR2) and lacks a transmembrane domain. Phylogenetic analysis showed that HcTIR1 was clustered with TIR of sea anemone Toll, and HcTIR2 was clustered with TIR of Drosophila Toll. HcToll-2 mRNA could be detected in the hepatopancreas and was upregulated after challenge with Escherichia coli and Staphylococcus aureus. Recombinant HcLRR protein with GST tag could bind to bacteria and also to LPS and PGN. Over-expression of both HcTIR1 and HcTIR2 induced drosomycin genes in Drosophila S2 cells. RNAi analysis showed that HcToll-2 was required for the expression of theromacin, which is a cysteine-rich antimicrobial peptide (AMP) gene. This research is the first report of an atypical Toll-like receptor HcToll-2 involved in antibacterial immunity through induction of AMP expression.
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China. Electronic address: renqian0402@126.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Ren
authors.affiliation: The Key Laboratory of Plant Cell Engineering and Germplasm Innovation of Ministry of Education/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China.
authors.forename: Jiang-Feng
authors.initials: JF
authors.lastname: Lan
authors.affiliation: Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Song
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
authors.forename: Kai-Min
authors.initials: KM
authors.lastname: Hui
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.affiliation: Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA. Electronic address: Yux@umkc.edu.
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Yu
authors.affiliation: The Key Laboratory of Plant Cell Engineering and Germplasm Innovation of Ministry of Education/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China. Electronic address: jxwang@sdu.edu.cn.
authors.forename: Jin-Xing
authors.initials: JX
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D016384:Consensus Sequence; D004331:Drosophila melanogaster; D006090:Gram-Negative Bacteria / Q000276:immunology; D006094:Gram-Positive Bacteria / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051193:Toll-Like Receptors / Q000737:chemistry / Q000502:physiology*; D015533:Transcriptional Activation / Q000276:immunology*; D049876:Unionidae / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology
chemical_list: D023181:Antimicrobial Cationic Peptides; D008070:Lipopolysaccharides; D051193:Toll-Like Receptors
keywords: Over-expression; RNAi; Tandem TIR domain; Theromacin; Toll