Interaction of avian infectious bronchitis virus S1 protein with heat shock protein 47

Abstract

Infectious bronchitis (IB) caused by a coronavirus is an important disease in chickens; it mainly affects respiratory and kidney systems. The IBV-S1 protein is an important structural and functional protein. To identify the interaction between the IBV-S1 proteins and to elucidate the possible involvement of S1 protein in IBV pathogenesis, a chicken kidney cDNA library was screened using a yeast two-hybrid system assay. HSP47, a molecular chaperone protein facilitating the folding and assembly, was found to interact specifically with the S1 protein. The interaction between S1 and HSP47 was verified by colocalization experiment and co-immunoprecipitation of HeLa cell lysates expressing both proteins. The mapping studies localized the critical S1 sequences for this interaction to amino acids 340-470. Based on these results, we speculate that HSP47 is a functional target of infectious bronchitis virus S1 protein in cells. This is the first report demonstrating the interaction of HSP47 with a structural protein of plusstrand RNA viruses, indicating a new drug target for IBV.

Key words: S1 protein, HSP47 protein, yeast two-hybrid, co-localization, co-immunoprecipitation, proteinprotein interaction.