Center for Comparative Medicine, University of California Davis, Davis, California, United States of America.
Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Veterans Affairs Medical Center, Atlanta, Georgia, United States of America.
PLoS One. 2014 Feb 5;9(2):e87914. doi: 10.1371/journal.pone.0087914. eCollection 2014.
Highly active antiretroviral therapy (HAART) can reduce levels of human immunodeficiency virus type 1 (HIV-1) to undetectable levels in infected individuals, but the virus is not eradicated. The mechanisms of viral persistence during HAART are poorly defined, but some reservoirs have been identified, such as latently infected resting memory CD4⁺ T cells. During latency, in addition to blocks at the initiation and elongation steps of viral transcription, there is a block in the export of viral RNA (vRNA), leading to the accumulation of multiply-spliced transcripts in the nucleus. Two of the genes encoded by the multiply-spliced transcripts are Tat and Rev, which are essential early in the viral replication cycle and might indicate the state of infection in a given population of cells. Here, the levels of multiply-spliced transcripts were compared to the levels of gag-containing RNA in tissue samples from RT-SHIV-infected rhesus macaques treated with HAART. Splice site sequence variation was identified during development of a TaqMan PCR assay. Multiply-spliced transcripts were detected in gastrointestinal and lymphatic tissues, but not the thymus. Levels of multiply-spliced transcripts were lower than levels of gag RNA, and both correlated with plasma virus loads. The ratio of multiply-spliced to gag RNA was greatest in the gastrointestinal samples from macaques with plasma virus loads <50 vRNA copies per mL at necropsy. Levels of gag RNA and multiply-spliced mRNA in tissues from RT-SHIV-infected macaques correlate with plasma virus load.
高效抗逆转录病毒疗法（HAART）可降低感染个体体内人类免疫缺陷病毒 1 型（HIV-1）的水平至无法检测，但病毒并未被消除。HAART 期间病毒持续存在的机制尚未明确，但已鉴定出一些病毒储存库，如潜伏感染的静止记忆 CD4⁺T 细胞。在潜伏期间，除了病毒转录起始和延伸步骤的阻断外，病毒 RNA（vRNA）的输出也被阻断，导致核内多剪接转录本的积累。多剪接转录本编码的两个基因是 Tat 和 Rev，它们在病毒复制周期的早期是必不可少的，可能表明特定细胞群体中的感染状态。在这里，将接受 HAART 治疗的感染 RT-SHIV 的恒河猴组织样本中的多剪接转录本水平与 gag 包含 RNA 的水平进行了比较。在开发 TaqMan PCR 检测时，鉴定了剪接位点序列变异。在胃肠道和淋巴组织中检测到多剪接转录本，但在胸腺中未检测到。多剪接转录本的水平低于 gag RNA 的水平，且两者均与血浆病毒载量相关。在尸检时血浆病毒载量<50vRNA 拷贝/ml 的恒河猴的胃肠道样本中，多剪接与 gag RNA 的比值最大。感染 RT-SHIV 的恒河猴组织中的 gag RNA 和多剪接 mRNA 水平与血浆病毒载量相关。
