Chromosomal Integration Sites And Histone Methylation Impact Of Latent HIV

Acquired Immunodeficiency Syndrome (AIDS) caused by human immune-deficiency virus (HIV) infection is a kind of infectious diseases. Highly active antiretroviral therapy (HAART) can effectively suppress the replication of HIV and retard the progress of the disease in AIDS treatment. However, HAART can’t eradicate HIV completely because of the presence of latent reservoirs.Elucidating mechanism of latency contributes to interpret the formation of latent reservoirs and provide a strategy for HIV eradication. According to previous studies, HIV latency is associated with integrated site, CpG methylation of LTR, and histone methlation. We performed researches to elucidate the mechanism of latency.We used the models formulated previously to amply the human genomic sequence flanking to integration site. After sequencing, we pooled the data to blast in NCBI and obtained information of integration site. Secondly, By using bisulfate to convert genomic DNA, we analyzed CpG methlation in5’LTR to explain association between HIV latency and CpG methlation level. Finally, we performed ChIP to investigate levels of H3K9methylation of HIV-1LTR in latent cell lines.According to the researches, most integration sites locate in introns of transcriptional genes and integration may prefer active genes. After analyzing methylation of CpG island, we found hypomethylation in CpG island of all latent models. CpG island methylation possibly did not correlate with establishment of HIV-1latency. Besides the former investigations, MTA, a broad-spectrum histone methylation inhibitor, was used to reactivate latent cells. We found only in Clone11, latent HIV could be partially reactivated by MTA. Reactivation of latent HIV showed that histone methylation could contribute to latency. For further demonstration, ChIP was performed to test the role of histone methylation and level of H3K9. About2.27-fold decrease of H3K9me2level was obsrved in cells with MTA treating compared to cells without MTA. These results clearly showed that MTA reactivated HIV by decreasing level of histone methylation and HIV latency was associated with presence of H3K9me2.We suggested that dimethylation of H3K9which was dependent on the environment created by the site of integration, played a significant role in initial establishment of HIV-1latency rather than CpG methylation. Our work elucidated the possible mechanism of HIV latency, provided a target for reactivating latent HIV and a strategy for eradication of HIV latent reservoirs with antiviral drugs.