Intervirology, 2014, 01, 116─120

Disruption of Polycomb Repressor Complex-Mediated Gene Silencing Reactivates HIV-1 Provirus in Latently Infected Cells

Cheol-Hee Yoon, Dai-Ho Jang, K Kim, S Park,H Kim, S Kim, S Chi, b Choi

Abstract

Objectives
Persistent HIV-1 infections are characterized by a long silent infection period in resting CD4+ T cells, which allows them to escape the host immune response. Several HIV-1 latency mechanisms have been reported, but the molecular mechanism underlying polycomb repressor complex (PRC)-mediated HIV-1 latency remains poorly understood.
Methods
Expression of PRC proteins in latent cells was measured by Western blot. Knockdowns of PRC genes were conducted by the specific siRNA and methylations at H3K27 on the proviral LTR were investigated by ChIP assay.
Results
PRC proteins (EED, BMI-1, and RNF2) were dramatically downregulated in latent cells after PMA treatment. The downregulation of PRC proteins was followed by a decrease in the methylation of H3K27 and ubiquitination of H2AK119 in the PMA-treated latent cells. siRNA knockdowns of EED and BMI-1 also enhanced HIV-1 reactivation significantly in latently infected cells. By contrast, proteasomal inhibitor MG132 successfully abrogated the PMA-induced downregulation of PRCs. In particular, di-/tri-methylations of histone-3 in the proviral LTR was absent from latent cells after PMA treatment.
Conclusions
This study shows that PRC is strongly related to the control of HIV-1 latency and that PRC-breaking agents may be helpful for purging HIV-1 from latent reservoirs.

• ISBN or ISSN: 0300-5526

• 본 연구는 질병관리본부 연구개발과제(과제번호 2010-N51001-00) 연구비를 지원받아 수행되었습니다.
• This research was supported by a fund(code 2010-N51001-00) by Research of Korea Centers for Disease Control and Prevention.