Cloning of neuraminidase (NA) gene and identification of its antiviral activity

Abstract

Neuraminidase not only works as an antigen, inducing target-specific antibodies, but also plays a role of  enzyme activity and destroys the sialic acid receptor required by virus infection of the host cell surface which  protects the host from virus damage. In order to explore a new idea to use neuraminidase (NA) gene and  produce disease-resistant transgenic poultry, prokaryotic expression vector pGEX-NA was constructed to  make NA polyclone antibody. Eukaryotic expression vector pcDNA3.0-NA and pcDNA3.0/EGFP-NA was  constructed to reveal its subcelluar location by immunofluorescence and enhanced green fluorescent fusion  protein (EGFP). Chicken embryonic fibroblast (CEF) cells were transfected with pcDNA3.0-NA and selected by  G418 for two weeks, the transfected cells were challenged by Newcastle disease virus (NDV), the morphology of CEF cells were observed to detect the antiviral ability of NA gene. CEF cells were incubated by the cell  lysates extracted from the NIH 3T3 cells, which were transfected with pcDNA3.0-NA. The results show that  pGEX-NA could express NA protein in vitro and NA polyclone antibody worked very well; immunofluorescence and EGFP fusion protein revealed that NA protein located at the cytoplasm near the membrane; NDV-CEF  inhibition experiment showed the NA protein could resist and delayed CEF cells from NDV infection.

Key words: Neuraminidase (NA), newcastle disease virus (NDV), antiviral activity, chicken embryonic fibroblast (CEF).