Effect Of Deletion Of The 81-92 Amino Acids Of The Ns1protein On Pathogenicityof The Influenzavirus

As a main pathogen,Influenza A virus(IAV)causes human respiratory infectious diseases and animal death.Also,asa single negative-strand RNA virusesbelonging to orthomyxoviridae virus,there areeight segments of RNA consisted in its genome,which could be divided into eighteen subtypes of HA and the eleven subtypes of NAaccording to the antigenicity of different virus HA and NA.Because of its high rate of infection by human raceand its high pathogenicity,it has repeatedly caused a worldwide pandemic for many times.Among them,H1N1,H5N1,H7N9 are particularly worthy of attention.In order to prevent and treat the influenza virus,on the one hand,it is necessary to strengthen the detection of influenza virus mutation and have targeted vaccination.On the other hand,from the source of virus spread,the spread of the virus in the crowd should be cut off.Under such circumstance,Oseltamivir,Amantadine,Interferon and other drugs for treatmentfor influenza patients could be used.The interferon is an important human virus defense system.However,the influenza virus NS1 protein has inhibitory effect on interferon.Therefore,it is important to study on influenza virus NS1 protein inhibits interferon stimulated gene expression and its mechanism.In this study,Influenza A virus A/PR/8/34(H1N1)was used as a template to construct a highly reproducible PR8 F virus on BALB/c mice and NS1 mutant virus with the technology of reverse genetic manipulation and site-directed mutagenesis.Then the biological characteristics of rescued virus were used for comparison research.Besides,the BALB/c mice were infected with virus,and the clinical manifestations and the survival rate of the infected mice were observed.Finally,the digital gene expression of infected mice through the next-generation sequencing technologies was analyzed to screen the differentially expressed genes in mice infected with different viruses and to study the effect of NS1 protein on the transcription level of interferon stimulated genes.The results showed that the reverse genetic platform of H1N1 subtype influenza virus was successfully constructed and the influenza virus PR8 F was rescued.By studying the pathogenicity of PR8 F to BALB / c mice,the attenuated strain of PR8 F through the comparative study of the pathogenicity of different PR8 F mutant strains to mice was found.Also,the differentially expressed genes of PR8 F and attenuated strain PR8 infected mice were screened and their effects on the signal pathway through the digital gene expression profile analysis were investigated.