The Mechanism Of Inhibitor Of Growth Protein 5 Acetylation In Regulating The Infection Of Bombyx Mori Nucleopolyhedrovirus

Bombyx mori is an economically important insect with a long history of domestication that supports the silk industry.B.mori nucleopolyhedrovirus(BmNPV)is a common pathogenic organism of silkworms and poses a great threat to sericulture.Therefore,the study of the interaction between baculovirus virus and insect hosts has always been a hot topic in the field of virology and entomology.In our laboratory,the results of differential omics analysis of protein acetylation modification before and after BmNPV infection in host cells showed that the acetylation modification levels of Inhibitor of growth protein 5(ING5)at three lysine residues(K136,K137,and K154)were significantly down-regulated after BmNPV infection.Existing studies have shown that ING5 plays an essential role in gene transcription,thus affecting cell proliferation and apoptosis.However,there are few reports on the function of ING5 in insects,especially the effect of acetylation modification on the function of the ING5 protein itself.To further explore the regulatory mechanism of ING5 and its acetylation modification in BmNPV infection,this study focused on the regulatory effect of ING5 protein and its acetylation modification on its function and its regulatory interaction with BmNPV.Firstly,the target gene ING5 was cloned from BmN cells by RT-PCR technology,and the recombinant transient expression plasmid was constructed.It was found that overexpression of ING5 could inhibit the activity of BmN cells and promote cell apoptosis.The immunoprecipitation results showed that the acetylation level of ING5 was significantly down-regulated after BmNPV invaded BmN cells.Lysine(K),whose acetylation modification level was significantly down-regulated,was site-mutated to glutamine(Q)to simulate acetylation modification and to arginine(R)to simulate deacetylation modification,using an overlapping PCR technique.The results showed that compared with wild-type ING5 protein,the acetylation of ING5 could significantly promote cell proliferation and inhibit cell apoptosis.By analyzing the mechanism,three lysine mutation sites are located in the nuclear localization sequence,and ING5 interacts with apoptosis-related protein P53 through this sequence.The interaction between ING5 and P53 was detected by yeast two-hybridization.The results showed that the two could interact,but the acetylation modification of ING5 blocked the interaction.The acetylation of ING5 can significantly reduce the stability of the P53 protein.Secondly,the effect of ING5 on virus proliferation during BmNPV infection of BmN cells was investigated.Analysis of viral genome,transcription,protein levels and progeny virus production showed that overexpression of ING5 significantly inhibited BmNPV proliferation.Acetylation of ING5 can promote viral proliferation,while deacetylation can inhibit viral proliferation.In conclusion,ING5 may promote host cell apoptosis in a P53-dependent manner,and the acetylation of sites K136,K137 and K154 changes the interaction between ING5 and P53,thus affecting cell apoptosis and viral proliferation.The results of this study can provide an experimental basis for further analysis of the role of ING5 family proteins in the process of BmNPV infection and also provide a new theoretical basis for the antiviral breeding of silkworms.