Molecular cloning and functional characterization of two duplicated two-cysteine containing type I interferon genes in rock bream Oplegnathus fasciatus.
Two type I interferon (IFN) genes, designated as rbIFN1 and rbIFN2, have been cloned and characterized in rock bream. They are both comprised of 5 exons and 4 introns, and are closely linked on the rock bream chromosome in a unique head-to-head configuration. Both genes encode 183 amino acid (aa) precursor with a putative 17 aa signal peptide in the N-terminal. Only one amino acid divergence is present between two IFNs. Compared with the type I IFNs in higher vertebrates, two rock bream IFNs possess conserved alpha helical structure and share approximately 20% identity in aa sequence. The highest aa sequence homology (83.2%) was found with European seabass IFNs. Phylogenetic analysis grouped two rock bream IFNs into the subgroup-d of two-cysteine containing IFNs. The gene synteny analysis revealed that they are orthologous with the zebrafish IFNφ4 on chromosome-12 and paralogous to each other, which are likely derived from a gene duplication event followed by an inversion. A number of cis-regulatory elements associated with immune response including 15 IRF and 6 NF-κB binding sites are predicted in the shared 4.5 kb 5'-flanking region. Highest constitutive expression of two IFNs was detected in blood cells and skin. Their expression in blood cells and head kidney was up-regulated by lipopolysaccharide, poly I:C, Edwardsiella tarda, Streptococcus iniae and iridovirus. Furthermore, recombinant rbIFN1 protein produced by E. coli induced a rapid and transient expression of the interferon inducible Mx gene in head kidney cells. These results suggest that two duplicated type I IFN genes are involved in rock bream host response to both viral and bacterial pathogens.
Department of Marine Life Sciences, Jeju National University, Jeju 690-756, Republic of Korea.
Qiang
Q
Wan
W D Niroshana
WD
Wicramaarachchi
Ilson
I
Whang
Bong-Soo
BS
Lim
Myung-Joo
MJ
Oh
Sung-Ju
SJ
Jung
Hyun Chul
HC
Kim
Sang-Yeob
SY
Yeo
Jehee
J
Lee
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001773:Blood Cells / Q000276:immunology / Q000378:metabolism; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D003545:Cysteine / Q000235:genetics / Q000276:immunology*; D004266:DNA Virus Infections / Q000276:immunology / Q000662:veterinary; D020609:Edwardsiella tarda / Q000502:physiology; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000662:veterinary; D004926:Escherichia coli / Q000235:genetics; D029941:Fish Proteins / Q000235:genetics / Q000276:immunology*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D020440:Gene Duplication; D015698:Genomic Library; D060226:Head Kidney / Q000276:immunology / Q000378:metabolism; D007113:Immunity, Innate; D007370:Interferon Type I / Q000235:genetics / Q000276:immunology*; D007497:Iridoviridae / Q000502:physiology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008969:Molecular Sequence Data; D064547:Myxovirus Resistance Proteins; D009928:Organ Specificity; D010473:Perciformes / Q000235:genetics / Q000276:immunology*; D010802:Phylogeny; D011070:Poly I-C / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment / Q000662:veterinary; D017386:Sequence Homology, Amino Acid; D013290:Streptococcal Infections / Q000276:immunology / Q000662:veterinary; D013291:Streptococcus / Q000502:physiology
D029941:Fish Proteins; D007370:Interferon Type I; D008070:Lipopolysaccharides; D064547:Myxovirus Resistance Proteins; D019204:GTP-Binding Proteins; D003545:Cysteine; D011070:Poly I-C