| Popis: |
Fish type I IFNs are classified into seven subgroups, including IFNe, IFNa, IFNd, IFNh, IFNb, IFNc and IFNf, which belong to three groups (I-III), while type II IFNs have only two members, IFN-γ and IFN-γrel. In the present study, four type I IFN (named as IFNc, IFNd1, IFNd2 and IFNh) and two type II IFN (IFN-γ and IFN-γrel) genes were identified in a perciform fish, the snakehead Channa argus, an aquaculturally important fish in some Asian countries, including China. The ORF of IFNc, IFNd1, IFNd2, IFNh, IFNG and IFNGrel genes consists of 549, 555, 591, 570, 606 and 564 nucleotides (nt), predicted to encode 182, 184, 196, 189, 201 and 187 amino acids (aa), respectively. The type I and type II IFNs share 58.2–73.5 % and 54.8–56.1 % amino acid sequence identities with those respectively in a perciform fish, mandarin fish (Siniperca chuatsi). It was found that the type I and II IFN genes are located at conserved loci when comparing to other fish. These snakehead IFNs are expressed constitutively in examined organs/tissues and are induced by polyI:C. In addition, four potential backbone groups (Group IIV) of type I IFNs, respectively represented by IFNe, IFNc, IFNf and IFNb in ancient teleost fish, were discussed in this study based on the known evidence, thus it provides a new hypothesis to understand the evolution of type I IFN in teleost fish. |
