Cloning, characterization, and expression analysis of LGP2 cDNA from goose, Anser cygnoides

Laboratory of genetics and physiology 2 ( LGP2: ) is a homologue of the retinoic acid inducible gene-I and melanoma differentiation associated gene 5 that lacks the caspase activation and recruitment domain required for signaling. It plays a pivotal role in host immune response. In this study, we cloned and characterized the full-length open reading frame ( ORF: ) sequence of LGP2 in the Qingyuan goose (Anser cygnoides) and evaluated the mRNA expression of this gene post infection with an H5N1 highly pathogenic avian influenza virus ( HPAIV: ). The full-length goose LGP2 ORF (2,028 bp) encoded a polypeptide of 675 amino acids. The deduced amino acid sequence contained 5 main overlapping structural domains-2 DEAD/DEAH box helicase domains, one conserved restriction domain of bacterial type III restriction enzyme, one helicase superfamily C-terminal domain and one C-terminal regulatory domain. Quantitative real-time PCR analysis indicated that goose LGP2 was constitutively expressed in all 19 investigated tissues, but the expression level was different among them. It was high expressed in the trachea, jejunum, bursa, kidney and heart, but low in the glandular stomach, lung, liver, spleen, crop and muscular stomach. A significant increase in the transcription of LGP2 was detected in the brain, spleen and lungs of geese post infection with H5N1 HPAIV versus uninfected tissues. These findings indicated that goose LGP2 was an important receptor that is involved in the host antiviral innate immune defense to H5N1 HPAIV in geese.