Nuclear Retention of Multiply Spliced HIV-1 RNA in Resting CD4+ T Cells

PLoS Pathogens

Kara G Lassen¹  Kasra X Ramyar¹  Robert F Siliciano¹  Yan Zhou¹  Justin R Bailey¹ 

[1] Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America

关键词: HIV-1;    T cells;    Highly-active antiretroviral therapy;    RNA viruses;    Gene expression;    RNA isolation;    RNA-binding proteins;    Viral persistence;    latency;   

DOI  :  10.1371/journal.ppat.0020068

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

HIV-1 latency in resting CD4+ T cells represents a major barrier to virus eradication in patients on highly active antiretroviral therapy (HAART). We describe here a novel post-transcriptional block in HIV-1 gene expression in resting CD4+ T cells from patients on HAART. This block involves the aberrant localization of multiply spliced (MS) HIV-1 RNAs encoding the critical positive regulators Tat and Rev. Although these RNAs had no previously described export defect, we show that they exhibit strict nuclear localization in resting CD4+ T cells from patients on HAART. Overexpression of the transcriptional activator Tat from non-HIV vectors allowed virus production in these cells. Thus, the nuclear retention of MS HIV-1 RNA interrupts a positive feedback loop and contributes to the non-productive nature of infection of resting CD4+ T cells. To define the mechanism of nuclear retention, proteomic analysis was used to identify proteins that bind MS HIV-1 RNA. Polypyrimidine tract binding protein (PTB) was identified as an HIV-1 RNA-binding protein differentially expressed in resting and activated CD4+ T cells. Overexpression of PTB in resting CD4+ T cells from patients on HAART allowed cytoplasmic accumulation of HIV-1 RNAs. PTB overexpression also induced virus production by resting CD4+ T cells. Virus culture experiments showed that overexpression of PTB in resting CD4+ T cells from patients on HAART allowed release of replication-competent virus, while preserving a resting cellular phenotype. Whether through effects on RNA export or another mechanism, the ability of PTB to reverse latency without inducing cellular activation is a result with therapeutic implications.

【 授权许可】

CC BY