Investigation On Cytidine Acetylation (ac4C) Of Coxsackievirus B3 Genome And Screening Of Antiviral Compounds

Enteroviruses are non-retro RNA viruses of Picornaviridae family which causes various infectious diseases,such as viral myocarditis,poliomyelitis and hand foot mouth disease,seriously threating public health.The molecular mechanism of enterovirus infection has not been fully understood.The genome of enterovirus is a single stranded sense RNA which can be directly translated into viral protein and proliferated by RNA replication.The translation,replication and stability of genomic RNA play a deci sive role in enterovirus infection.In my master program,I have been working on two research projects related to enterovirus genomic RNA,in order to explore the mechanism for survival of enterovirus in host cells and screen potential therapeutic compounds against enterovirus infection.The first project is to explore the modification of enterovirus genomic RNA.N4-acetylcytidine(ac4C)is a newly discovered epigenetic modification of m RNA,which is catalyzed by the acetyltransferase NAT10 and plays an important role in promoting the stability and translation efficiency of m RNA.Previous studies have found that ac4 C modification is related to infection of RNA viruses.For example,ac4 C modification in the transcripts of retrovirus HIV-1 can promote HIV-1 replication.However,the presence of ac4 C in non-retroviral genomes and its effect on viral replication are still unknown.In this project,we used coxsackievirus B3,a typical enterovirus,as a model to carry out a preliminary study.The overall hypothesi s is that ac4 C modification exists in the genomic RNA of CVB3 infection,which can effect viral replication.To verify this hypothesis,we examined the levels of ac4 C modification in CVB3 infection,and found that CVB3 infection elevated ac4 C level of RNA in cells infected by CVB3.We further confirmed the existence of ac4 C modification in CVB3 genomic RNA which was mainly distributed at the 3' end.Functional studies showed that knockout of NAT10 could significantly inhibit CVB3 infection,and the complementary expression of this protein could reverse this inhibition.Therefore,we preliminarily proved that ac4 C modification existed in CVB3 genome which benefited CVB3 replication.The second project is to screen anti-enterovirus drugs from RNA binding polymers.Recent studies have shown that amidines and guanidines have nucleic acid chain binding activity and the compounds have been used in anti-bacterial therapy,but their antiviral activity is not clear.In this study,we tested 53 polyguanidine compounds and 4polyamidine compounds for their antiviral activity using CVB3.As a results,three polyguanidine compounds with high antiviral activities were screened out.Through the comparison of molecular structure,we found that the compounds with closer guanidine groups and better hydrophilicity generally exerted better antiviral activity.In summary,the research project has preliminarily shown a novel mechanism affecting enerovirus infection related to ac4 C modification in viral genomic RNA.In addition,the study has also screened out new candidate compounds as potential anti-enterovirus drugs.