Interaction Between M1 And NA Proteins Of Influenza Virus And Its Role In Virus Budding

Influenza virus is an enveloped virus,assemble at membrane and then release from host by budding.several studies have provided evidence that the Ml protein,doesn’t like the NA,does not have the capability to bud from plasma membrane of host cell,and it can only be carried by the virus membrane protein via interaction between them,however,the function of this interaction in virus budding remains unclear,and the region of M1 that interact with NA has not been well mapped.Hereby,The above problems were studied as follows via BiFC and VLP experiments:1.The virus A/WSN/1933(H1N1)was infected and amplified in MDCK cells,and the viral RNA was extracted and reverse transcribed.NA and M1 and its truncates was amplified by PCR.The obtained gene fragments were cloned into BIFC working vector and Flag,ha eukaryotic expression vector respectively.2.The interaction between Ml and NA was studied by BIFC experiment.VC-M1 and VN-NA transfected into 293T cells could produce strong fluorescence signal,indicating that there was interaction between them.VLP experiments confirmed that NA protein can be sprouted independently,M1 protein can not be independent budding,and M1 protein can interact with NA protein and be carried together common budding.3.The interaction between M1 protein and NA protein was confirmed by BIFC experiment and VLP experiment.The results showed that the 160 amino acids of M1 protein were in the interaction region with NA,and 60-252aa did not invlove in interaction.4.the deletion of 20aa at both ends of the M1-1-160aa region will decrease its expression in the cells,indicating that the N-terminal 160aa of the M1 protein plays a key role in its protein stability.At the same time,the crystal structure analysis of M1 protein also confirmed the importance of its 1～160aa to maintain protein structure stability.This study reveals the interaction regions between M1 and NA proteins,and the function of this interaction in virus budding of influenza virus,further complete the mechanism of influenza virus budding.