Influence of gag and RRE Sequences on HIV-1 RNA Packaging Signal Structure and Function
| Autor: | Joshua D. Brown, Michael F. Summers, Aishwarya S. Iyer, John Collins, Alice Telesnitsky, Siarhei Kharytonchyk, Krista L. Stilger, Saif Yasin |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Base pair Active Transport Cell Nucleus Heterologous Context (language use) gag Gene Products Human Immunodeficiency Virus Article 03 medical and health sciences Retrovirus Downstream (manufacturing) Structural Biology Humans Nuclear export signal Molecular Biology biology Chemistry Virus Assembly RNA rev Gene Products Human Immunodeficiency Virus biology.organism_classification Phenotype Cell biology HEK293 Cells 030104 developmental biology HIV-1 Nucleic Acid Conformation RNA Viral |
| Zdroj: | Journal of Molecular Biology. 430:2066-2079 |
| ISSN: | 0022-2836 |
| Popis: | The packaging signal (Ψ) and Rev responsive element (RRE), enable unspliced HIV-1 RNAs’ export from the nucleus and packaging into virions. For some retroviruses, engrafting Ψ onto a heterologous RNA is sufficient to direct encapsidation. In contrast, HIV-1 RNA packaging requires 5′ leader Ψ elements plus poorly defined additional features. We previously defined minimal 5′ leader sequences competitive with intact Ψ for HIV-1 packaging, and here examined the potential roles of additional downstream elements. The findings confirmed that together, HIV-1 5′ leader Ψ sequences plus a nuclear export element are sufficient to specify packaging. However, RNAs trafficked using a heterologous export element did not compete well with RNAs using HIV-1’s RRE. Furthermore, some RNA additions to well-packaged minimal vectors rendered them packaging-defective. These defects were rescued by extending gag sequences in their native context. To understand these packaging defects’ causes, in vitro dimerization properties of RNAs containing minimal packaging elements were compared to RNAs with sequence extensions that were or were not compatible with packaging. In vitro dimerization was found to correlate with packaging phenotypes, suggesting that HIV-1 evolved to prevent 5′ leader residues’ base pairing with downstream residues and misfolding of the packaging signal. Our findings explain why gag sequences have been implicated in packaging and show that RRE’s packaging contributions appear more specific than nuclear export alone. Paired with recent work showing that sequences upstream of Ψ can dictate RNA folds, the current work explains how genetic context of minimal packaging elements contributes to HIV-1 RNA fate determination. |
| Databáze: | OpenAIRE |
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