Cloning and Sequencing of the Full-length cDNA of Mx Protein from Mandarinfish

Mx protein is one of the classes of antiviral proteins induced by type I interferons (IFN). A full-length cDNA of mandarinfish (Siniperca chuatsi) Mx gene was obtained using reverse transcription polymerase chain reaction (RT-PCR) and RACE (rapid amplification of cDNA ends) polymerase chain reaction (PCR) amplification of total RNA extracted from liver of a mandarinfish which was infected with Infectious spleen and kidney necrosis virus (ISKNV) (GenBank accession No.AY392097). The result of sequence analysis indicates that the 2.4kb mandarinfish Mx cDNA contains an open reading frame (ORF) of 1881nt encoding a 627 amino acid protein whose deduced protein molecular weight is 71.5kDa. The alignment of the deduced mandarinfish Mx protein amino acid sequence with that of other species shows that the Mx protein of mandarinfish contains a triparitite guanosine-5’-triphosphate (GTP)-binding motif (GXXXSGKS/T, DXXG, T/NKXD), a signature of the dynamin family (LPRGS/ KGIVTR), and a highly conserved leucine zipper motif in the C-terminal region of the protein, which are conserved in all IFN-induced Mx proteins of vertebrates.