Abstract：Akirin, a conserved nuclear factor, is associating with immune functions in animal via regulating cytokine transcription and immune cell chemotaxis. Here, an akirin1 cDNA sequence (Paakirin1) from ayu (Plecoglossus altivelis) was cloned. The Paakirin1 was 1817 bp in length encoded a 182 aa polypeptide with a molecular weight of 20.68 kD(GenBank accession No. KP278589). Sequence comparisons for similarity showed that Paakirin1 was highly similar to akirin1 in fish, such as, rainbow trout (Oncorhynchus mykiss) akirin1 (86%), followed by Arctic char (Salvelinus alpinus) and Atlantic salmon (Salmo salar) akirin1 (85%). Multiple sequence alignment analysis showed that Paakirin1 possessed nuclear localization signal. Phylogenetic analysis showed that fish akirin1 genes grouped tightly into one big cluster. Paakirin1 clustered together with the akirin1s of salmonidae family. Semi-quantitative PCR data showed that Paakirin1 was mainly expressed in head-kidney, spleen, intestine, and monocytes macrophages. After Vibrio anguillarum infection, Paakirin1 mRNA was up-regulated in head-kidney and spleen, while down-regulated in intestine. Furthermore, Paakirin1 mRNA was also up-regulated in monocytes macrophages after lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (PolyI:C) treatment. After Paakirin1 siRNA treatment in monocytes macrophages, the mRNA expression of interleukin-1β (IL-1β) and tumor necrosis factor (TNF) induced by V. anguillarum was unaltered, while its chemotaxis toward to recombinant CXC chemokine ligand 8 (CXCL8) protein was down-regulated. In summary, Paakirin1 alters its expression after infection and mediates chemotaxis of ayu monocytes macrophages. The research provides a theoretical basis and reference for the further investigation of function and regulation of monocytes macrophages in fish.
[1]Magnadottir B.Innate immunity of fish (overview)[J]. [J].Fish & Shellfish Immunology, 2006, 20(2):137-151[2]Whyte S K.The innate immune response of finfish--a review of current knowledge[J].[J].Fish & Shellfish Immunology, 2007, 23(6):1127-1151[3]Magnadottir B.Immunological control of fish diseases[J]. [J].Marine Biotechnology (NY), 2010, 12(4):361-379[4]Kawasaki T, Kawai T.Toll-like receptor signaling pathways[J].[J].Frontiers in Immunology, 2014, 5(1):461-468[5]Galindo R C, Doncel-Perez E, Zivkovic Z, et al.Tick subolesin is an ortholog of the akirins described in insects and vertebrates[J]. [J].Developmental & Comparative Immunology, 2009, 33(4):612-617[6]Marshall A, Salerno M S, Thomas M, et al.Mighty is a novel promyogenic factor in skeletal myogenesis[J]. [J].Experimental Cell Research, 2008, 314(5):1013-1029[7]Komiya Y, Kurabe N, Katagiri K, et al.A novel binding factor of 14-3-3beta functions as a transcriptional repressor and promotes anchorage-independent growth, tumorigenicity, and metastasis[J]. [J].The Journal of Biological Chemistry, 2008, 283(27):18753-18764[8]Nowak S J, Aihara H, Gonzalez K, et al.Akirin links twist-regulated transcription with the Brahma chromatin remodeling complex during embryogenesis[J]. [J].PLoS Genetics, 2012, 8(3):e1002547-e1002547[9]Goto A, Matsushita K, Gesellchen V, et al.Akirins are highly conserved nuclear proteins required for NF-kappaB-dependent gene expression in drosophila and mice[J].[J].Nature Immunology, 2008, 9(1):97-104[10]Xue X, Wang L, Chen Y, et al.Identification and molecular characterization of an Akirin2 homolog in Chinese loach (Paramisgurnus dabryanus)[J].[J].Fish & Shellfish Immunology, 2014, 36(2):435-443[11]Macqueen D J, Johnston I A.Evolution of the multifaceted eukaryotic akirin gene family[J]. [J].BMC Evolutionary Biology, 2009, 9(1):34-34[12]Salerno M S, Dyer K, Bracegirdle J, et al.Akirin1 (Mighty), a novel promyogenic factor regulates muscle regeneration and cell chemotaxis[J]. [J].Experimental Cell Research, 2009, 315(12):2012-2021[13]Bonnay F, Nguyen X H, Cohen-Berros E, et al.Akirin specifies NF-kappaB selectivity of Drosophila innate immune response via chromatin remodeling[J].[J].The EMBO Journal, 2014, 33(20):2349-2362[14]Yan J, Dong X, Kong Y, et al.Identification and primary immune characteristics of an amphioxus akirin homolog[J]. [J].Fish & Shellfish Immunology, 2013, 35(2):564-571[15]Kasthuri S R, Umasuthan N, Whang I, et al.Akirin2 homologues from rock bream, Oplegnathus fasciatus: Genomic and molecular characterization and transcriptional expression analysis[J]. [J].Fish & Shellfish Immunology, 2013, 35(3):740-747[16]Qu F, Xiang Z, Zhang Y, et al.The identification of the first molluscan Akirin2 with immune defense function in the Hong Kong oyster Crassostrea hongkongensis[J]. [J].Fish & Shellfish Immunology, 2014, 41(2):455-466[17]Lu X J, Hang X Y, Yin L, et al.Sequencing of the first ayu (Plecoglossus altivelis) macrophage transcriptome and microarray development for investigation the effect of LECT2 on macrophages[J]. [J].Fish & Shellfish Immunology, 2013, 34(2):497-505[18]Huang Z A, Chen J, Lu X J, et al.Alteration on the expression of ayu coagulation factor X gene upon Listonella anguillarum infection[J]. [J].Zoology Research, 2011, 35(5):492-498[19]Livak K J, Schmittgen T D.Analysis of relative gene expression data using real-time quantitative PCR and the 2?ΔΔCT method[J]. [J].Methods, 2001, 25(4):402-408[20]Chu C Q, Lu X J, Li C H, et al.Molecular characterization of a CXCL8-like protein from ayu and its effect on chemotaxis of neutrophils and monocytes/macrophages[J].[J].Gene, 2014, 548(1):48-55[21]He Y Q, Chen J, Lu X J, et al.Characterization of P2X7R and its function in the macrophages of ayu, Plecoglossus altivelis[J]. [J].PLoS One, 2013, 8(2):e57505-e57505[22]Ma Q Q, Jiao W J, Wang Z Y, et al.Tissue specificity and species superiority of cathelicidin gene expression in Chinese indigenous Min pigs[J]. [J].Livestock Science, 2014, 161(1):36-40
