AIV Viral Protein NS1 Affects The Splicing Of M Segment Via Interacting With YBX1

Avian influenza is the zoonotic diseases caused by influenza A virus.In recent years,the overspreading of influenza A virus resulting in human casualties and hitting the poultry farming.The influenza A virus belongs to the orthomyxovirus family and is a negative-strand RNA virus with 8 segments of the genome.The nonstructural protein NS1 of influenza A virus is a multifunctional protein involved in several activities during viral infection,including inhibition of host immune response,regulation of v RNA synthesis,promotion of viral m RNA splicing and translation,regulation of viral replication cycles and so on.In this study,we focus on the mechanism of NS1 affects M segment.In this study,it was found that the M2 m RNA level produced by the spliced M-segment was about 7 times to without NS1 expression,while the change of M1 m RNA level in M-segment was not obvious,which indicated that NS1 could promote the splicing of M-segment of viral genome.Most of the functions of NS1 protein are mainly achieved by protein-protein or protein-RNA interaction.The m RNA splicing of virus in cells depends on the splicing factor in host cells.In this study,we use the tandem affinity chromatography,MS / MS mass spectrometry,and found numbers of host proteins interacting with NS1,including YWHAB,TRIM27,YBX1,PABPC4 and so on.The interaction between splicing factor YBX1 and NS1 was determined by immunoprecipitation method,which is independent of the direct interaction of RNA.Immunofluorescence localization studies have shown that interaction between NS1 and YBX1 may function by altering the localization of YBX1 in cells.Therefore,we knock-down the relative cell protein in A549 cells,studies have shown that when we knock-down the YBX1 protein in A549 cells,the m RNA level of M1 and M2 have a reduction;but at the protein level,M2 expression decreased sharply.This suggests that the interaction between NS1 and YBX1 can affect the expression of the M-segment of the viral genome.The truncated protein domain and immunoprecipitation technique were used to find and demonstrate that the key domain of the interaction between YBX1 and NS1 is the cold shock domain.In conclusion,this study found the splicing factor involved in NS1 regulation of M-segment expression.It is proved that YBX1 plays an important role in NS1 regulation of M-segment expression,and the key domain of YBX1 is the cold shock domain.Clarifying the interaction between NS1 and YBX1 and its effect on M-segment splicing helps us to understand the life history of the virus more clearly,reveal the pathogenesis of influenza A virus,and target drugs and vaccines targeting NS1 Development to provide some ideas.In conclusion,this study found the splicing factor involved in NS1 regulation of M segment expression.Our research proved that YBX1 plays an important role in regulation of M sement by NS1,and the key domain of YBX1 is Cold Shock Domain.