Ooms Marcel, Huthoff Hendrik, Russell Rodney, Liang Chen, Berkhout Ben
Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
J Virol. 2004 Oct;78(19):10814-9. doi: 10.1128/JVI.78.19.10814-10819.2004.
The genome of retroviruses, including human immunodeficiency virus type 1 (HIV-1), consists of two identical RNA strands that are packaged as noncovalently linked dimers. The core packaging and dimerization signals are located in the downstream part of the untranslated leader of HIV-1 RNA-the Psi and the dimerization initiation site (DIS) hairpins. The HIV-1 leader can adopt two alternative conformations that differ in the presentation of the DIS hairpin and consequently in their ability to dimerize in vitro. The branched multiple-hairpin (BMH) structure folds the poly(A) and DIS hairpins, but these domains are base paired in a long distance interaction (LDI) in the most stable LDI conformation. This LDI-BMH riboswitch regulates RNA dimerization in vitro. It was recently shown that the Psi hairpin structure is also presented differently in the LDI and BMH structures. Several detailed in vivo studies have indicated that sequences throughout the leader RNA contribute to RNA packaging, but how these diverse mutations affect the packaging mechanism is not known. We reasoned that these effects may be due to a change in the LDI-BMH equilibrium, and we therefore reanalyzed the structural effects of a large set of leader RNA mutations that were presented in three previous studies (J. L. Clever, D. Mirandar, Jr., and T. G. Parslow, J. Virol. 76:12381-12387, 2002; C. Helga-Maria, M. L. Hammarskjold, and D. Rekosh, J. Virol. 73:4127-4135, 1999; R. S. Russell, J. Hu, V. Beriault, A. J. Mouland, M. Laughrea, L. Kleiman, M. A. Wainberg, and C. Liang, J. Virol. 77:84-96, 2003). This analysis revealed a strict correlation between the status of the LDI-BMH equilibrium and RNA packaging. Furthermore, a correlation is apparent between RNA dimerization and RNA packaging, and these processes may be coordinated by the same LDI-BMH riboswitch mechanism.
逆转录病毒的基因组，包括1型人类免疫缺陷病毒（HIV-1），由两条相同的RNA链组成，这些RNA链以非共价连接的二聚体形式被包装。核心包装和二聚化信号位于HIV-1 RNA未翻译前导区的下游部分——ψ序列和二聚化起始位点（DIS）发夹结构。HIV-1前导区可以呈现两种不同的构象，这两种构象在DIS发夹结构的呈现方式上有所不同，因此在体外二聚化的能力也不同。分支多发夹（BMH）结构折叠了poly(A)和DIS发夹结构，但在最稳定的长距离相互作用（LDI）构象中，这些结构域通过长距离相互作用进行碱基配对。这种LDI-BMH核糖开关在体外调节RNA二聚化。最近的研究表明，ψ发夹结构在LDI和BMH结构中的呈现方式也有所不同。一些详细的体内研究表明，前导RNA中的序列对RNA包装有贡献，但这些不同的突变如何影响包装机制尚不清楚。我们推测这些影响可能是由于LDI-BMH平衡的变化，因此我们重新分析了之前三项研究（J. L. Clever、D. Mirandar, Jr.和T. G. Parslow，《病毒学杂志》76:12381-12387，2002；C. Helga-Maria、M. L. Hammarskjold和D. Rekosh，《病毒学杂志》73:4127-4135，1999；R. S. Russell、J. Hu、V. Beriault、A. J. Mouland、M. Laughrea、L. Kleiman、M. A. Wainberg和C. Liang，《病毒学杂志》77:84-96，2003）中呈现的大量前导RNA突变的结构效应。该分析揭示了LDI-BMH平衡状态与RNA包装之间存在严格的相关性。此外，RNA二聚化与RNA包装之间也存在明显的相关性，并且这些过程可能由相同的LDI-BMH核糖开关机制协调。
