First Cloning, Tissue-specific Expression and Molecular Characterization of RIG-I Gene in Whooper Swan

To investigate the molecular characteristics of the RIG-I gene of whooper swan, RIG-I gene was cloned, sequenced and characterized, and the relative expression levels of the RIG-I gene in five tissues of whooper swans were determined by Real-time Quantitative PCR (qPCR).The RIG-I gene of whooper swan has a 2964 bp CDS that encode a peptide of 987 amino acids, RIG-I is widely expressed in various tissues of the whooper swan, but the expression levels show certain differences.The homology analysis indicated that the RIG-I gene of whooper swan has a more than 90% homology with other Anseriformes birds including mallard, swan goose, black swan and mute swan.Phylogenetic analysis showed that RIG-I gene of whooper swan and other birds have grouped in a separate branch.Gene alignment analysis revealed that RIG-I gene of swan has an extra low complexity region compared with that of non-swan birds.The amino acid alignment analysis showed that RIG-I of swan has a specific S62G phosphorylation site mutation compared with that of other birds and ubiquitination/phosphorylation mutation sites (RNF122, CK2, and REUL I) which differ from that of human.This is the first cloning and characterization of RIG-I gene from whooper swan.It may enhance our understanding of the molecular response mechanism of RIG-I against the influenza virus.