Research On The Mechanism Of Proteasome Subunit PSMD2 Regulating HIV-1 Gene Transcription Elongation

AIDS is still one of the major diseases that need to be solved urgently in the world.Although existing retroviral inhibitors can inhibit the replication of HIV-1,it is still impossible to eradicate HIV-1 in the latent period.HIV-1 in the latent period can integrate its genome into resting T cells to survive.Explaining the latent mechanism of HIV-1 transcription is of great significance for the complete cure of HIV-1.Existing studies have found that the proteasome is involved in the process of gene transcription regulation,and down-regulation or inhibition of the proteasome can promote transcriptional activation of HIV-1 genes,thereby promoting efficient transcription.P-TEFb is a positive transcription elongation factor composed of CDK9 and CycT1,which plays an important role in the process of HIV-1 gene transcription.This project uses SILAC quantitative proteomics technology and found that knocking down the protein expression level of kinase CDK9 will reduce the phosphorylation level on the 16th serine of PSMD2 protein.Endogenous immunoprecipitation and in vitro binding experiments proved that PSMD2 has a direct interaction with CDK9,and 16O/18O-ATP quantitatively labeled in vitro kinase experiments proved that PSMD2 can be directly phosphorylated by CDK9.Through transcriptional activity analysis,it was found that the phosphorylation of the S16 position of PSMD2 can promote the basic transcription level of HIV-1 and weaken the binding of PSMD2 to LARP7,HEXIM1 and CDK9 in the 7SK snSNP component,indicating that PSMD2 phosphorylation is very likely to regulate the 7SK snSNP dissociate.Finally,it was found that knocking down the level of PSMD2 would inhibit the transcription level of HIV-1 gene and weaken the interaction between CDK9 and Brd4.In summary,this project mainly studies the function of the proteasome subunit PSMD2 in the regulation of HIV-1 gene transcription elongation,and proves that the proteasome subunit PSMD2 plays a very important role in the process of HIV-1 gene transcription elongation.The phosphorylation regulation of the proteasome is further explored.The role of the proteasome in the regulation of HIV-1 gene transcription extension has been further explained and supplemented,and the mechanism of the HIV-1 gene transcription regulation process has been enriched,providing new ideas and targets for the treatment of HIV-1.