# Role of RNA Methylation in Regulating HIV Proviral Expression

> **NIH NIH R56** · OHIO STATE UNIVERSITY · 2021 · $373,757

## Abstract

PROJECT SUMMARY
 Although HAART treatment is successful to block active replication of HIV in AIDS patients, it does not
completely eradicate the infection. HIV latent reservoirs remain as a major obstacle for complete elimination of
HIV viruses and cure of the infection. Investigation of host machineries that regulate HIV proviral expression
will help to improve the understanding of the stage of HIV latent infection. It will also provide new strategies to
perturb host regulatory factors for eliminating latent HIV. We characterized that one of NSUN RNA m5C
methyltransferases (m5C-MTases), NSUN1/NOP2, restricts HIV replication, suppresses HIV proviral
expression, and promotes viral latency. The impact of m5C methylation catalyzed by NSUN m5C-MTases
(NSUN1-7) on HIV replication still remains largely unknown but starts to unfold. In this proposal, we will initiate
the in-depth examination of NSUN m5C-MTases as regulators of HIV proviral expression. For aim 1, we will
employ the ultra-sensitive reverse transcription droplet digital PCR (RT-ddPCR) assays to measure various
HIV transcripts in cells depleted of NSUN m5C-MTases, which will provide a high-resolution profiling of their
effect on HIV proviral expression. Furthermore, we will confirm whether the enzymatic activity of NSUN m5C-
MTases is required. We will also determine whether NSUN m5C-MTases interferes with HIV post-
transcriptional events, including HIV mRNA stability and translation. For aim 2, we will investigate the impact of
NSUN m5C-MTases on the activation of P-TEFb and RNA Pol-II that play a critical role in promoting HIV
transcription. Our results showed that the loss of NSUN1 reduces m5C methylation of HIV TAR RNA and that
its MTase catalytic domain (MTD) prevents HIV Tat-TAR interaction, indicating that m5C methylation of TAR
may regulate its interaction with Tat directly. We will identify the m5C methylation site(s) of TAR catalyzed by
NSUN m5C-MTases and further determine its role in modulating Tat-TAR interaction. For aim 3, we will
investigate the role of NSUN m5C-MTases in regulation of HIV 5’ and 3’ UTRs’ viral functions. We will
determine whether NSUN m5C-MTases bind with HIV 5’ and 3’ UTRs as well as contribute to their m5C
methylation. Since 5’ and 3’ UTRs of HIV mRNA play a critical role in regulation of HIV proviral expression epi-
transcriptionally, we will determine whether m5C methylation of HIV 5’ and 3’ UTRs affects mRNA stability and
protein translation. Furthermore, it has been recently shown that NSUN m5C-MTases also play an important
role in regulating host cellular epi-transcriptomics. Thus, we will determine their functional impact on host gene
expression in HIV latently infected CD4+ T cells. Overall, this proposal will comprehensively investigate NSUN
m5C-MTases as novel regulators of HIV proviral expression. We believe that these studies will significantly
improve our understanding of host-HIV interactions. From these studies, we will confirm whether memb...

## Key facts

- **NIH application ID:** 10426418
- **Project number:** 1R56AI157872-01A1
- **Recipient organization:** OHIO STATE UNIVERSITY
- **Principal Investigator:** Jian Zhu
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $373,757
- **Award type:** 1
- **Project period:** 2021-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10426418

## Citation

> US National Institutes of Health, RePORTER application 10426418, Role of RNA Methylation in Regulating HIV Proviral Expression (1R56AI157872-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10426418. Licensed CC0.

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