Evolution of akirin family in gene and genome levels and coexpressed patterns among family members and rel gene in croaker.
Akirins, which are highly conserved nuclear proteins, are present throughout the metazoan and regulate innate immunity, embryogenesis, myogenesis, and carcinogenesis. This study reports all akirin genes from miiuy croaker and analyzes comprehensively the akirin gene family combined with akirin genes from other species. A second nuclear localization signal (NLS) is observed in akirin2 homologues, which is not in akirin1 homologues in all teleosts and most other vertebrates. Thus, we deduced that the loss of second NLS in akirin1 homologues in teleosts likely occurred in an ancestor to all Osteichthyes after splitting with cartilaginous fish. Significantly, the akirin2(2) gene included six exons interrupted by five introns in the miiuy croaker, which may be caused by the intron insertion event as a novel evidence for the variation of akirin gene structure in some species. In addition, comparison of the genomic neighborhood genes of akirin1, akirin2(1), and akirin2(2) demonstrates a strong level of conserved synteny across the teleost classes, which further proved the deduction of Macqueen and Johnston 2009 that the produce of akirin paralogues can be attributed to whole-genome duplications and the loss of some akirin paralogues after genome duplications. Furthermore, akirin gene family members and relish gene are ubiquitously expressed across all tissues, and their expression levels are increased in three immune tissues after infection with Vibrio anguillarum. Combined with the expression patterns of LEAP-1 and LEAP-2 from miiuy croaker, an intricate network of co-regulation among family members is established. Thus, it is further proved that akirins acted in concert with the relish protein to induce the expression of a subset of downstream pathway elements in the NF-kB dependent signaling pathway.
Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China.
Tianxing
T
Liu
College of Animal Science and Veterinary Medicine, Jilin Agriculture University, Changchun 130118, China.
Yunhang
Y
Gao
Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China. Electronic address: tianjunxu@163.com.
Tianjun
T
Xu
D000595:Amino Acid Sequence; D000818:Animals; D019295:Computational Biology; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D020573:Genes, rel; D016678:Genome; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics; D010473:Perciformes / Q000502:physiology*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome
C559424:Akirin1 protein, mouse; D029941:Fish Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D014157:Transcription Factors
Akirin; Evolution; Expression patterns; Gene structure; NLS