title: Identification, origin and evidence for retained functionality of two IκBα paralogs in Megalobrama amblycephala.
abstract: IκBα plays an essential role in the innate immune response in mammals. We found two functional IκBα paralogs, originating from the teleost-specific genome duplication, in Megalobrama amblycephala: maIκBαa and maIκBαb. Their size (936/933 bp) and structure are highly analogous to known orthologs. mRNA expression was analysed by qPCR in spleen, liver, kidney, intestine and gills. Apart from maIκBαb in gills (<0.001-fold), both paralogs were constitutively expressed in all tissues. Differential expression was observed in gills (high for maIκBαa) and liver: maIκBαa - 2nd lowest (0.47), maIκBαb - 2nd highest (4.25). Both paralogs (mRNA) were upregulated in liver, spleen and kidney after a bacterial (Aeromonas hydrophila) challenge. In spleen, expressions peaked at 12 h post injection (hpi) (maIκBαa = 14.3-fold, maIκBαb = 21.3-fold), but only maIκBαb was highly upregulated at 4, 24 and 120 hpi. In liver, both were upregulated early, but maIκBαa peaked at 4 hpi (15.2-fold) and maIκBαb at 12 hpi (9.8-fold). In kidney, maIκBαa was highly upregulated only at 12 hpi (8.7-fold), and maIκBαb at 4 (peak - 8.2-fold), 12 and 24 hpi. The results indicate that both IκBα paralogs have retained their functionality, that they are structurally and functionally homologous to IκBα orthologs described in other animal species, and that they both play an important role in the innate immune system of M. amblycephala.
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Ivan
authors.initials: I
authors.lastname: Jakovlić
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Changde, 41500, China. Electronic address: wangwm@mail.hzau.edu.cn.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wang
mesh_terms: D016980:Aeromonas hydrophila / Q000276:immunology*; D000818:Animals; D005075:Biological Evolution; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003530:Cyprinidae / Q000276:immunology*; D005393:Fish Diseases / Q000276:immunology*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D020440:Gene Duplication; D005880:Gills / Q000378:metabolism*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology*; D007113:Immunity, Innate; D000072000:NF-KappaB Inhibitor alpha / Q000235:genetics / Q000378:metabolism*; D040681:Structural Homology, Protein; D059467:Transcriptome
chemical_list: D029941:Fish Proteins; D000072000:NF-KappaB Inhibitor alpha
keywords: Fish; Functional annotation; Gene expression; Genome duplication; Innate immunity; NFκBiα