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Vallejos M, Deforges J, Plank TDM, Letelier A, Ramdohr P, Abraham CG, Valiente-Echeverría F, Kieft JS, Sargueil B, López-Lastra M. Activity of the human immunodeficiency virus type 1 cell cycle-dependent internal ribosomal entry site is modulated by IRES trans-acting factors. Nucleic Acids Res 2011; 39:6186-200. [PMID: 21482538 PMCID: PMC3152342 DOI: 10.1093/nar/gkr189] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The 5′ leader of the human immunodeficiency virus type 1 (HIV-1) genomic RNA harbors an internal ribosome entry site (IRES) that is functional during the G2/M phase of the cell cycle. Here we show that translation initiation mediated by the HIV-1 IRES requires the participation of trans-acting cellular factors other than the canonical translational machinery. We used ‘standard’ chemical and enzymatic probes and an ‘RNA SHAPE’ analysis to model the structure of the HIV-1 5′ leader and we show, by means of a footprinting assay, that G2/M extracts provide protections to regions previously identified as crucial for HIV-1 IRES activity. We also assessed the impact of mutations on IRES function. Strikingly, mutations did not significantly affect IRES activity suggesting that the requirement for pre-formed stable secondary or tertiary structure within the HIV-1 IRES may not be as strict as has been described for other viral IRESes. Finally, we used a proteomic approach to identify cellular proteins within the G2/M extracts that interact with the HIV-1 5′ leader. Together, data show that HIV-1 IRES-mediated translation initiation is modulated by cellular proteins.
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Affiliation(s)
- Maricarmen Vallejos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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Vallejos M, Ramdohr P, Valiente-Echeverría F, Tapia K, Rodriguez FE, Lowy F, Huidobro-Toro JP, Dangerfield JA, López-Lastra M. The 5'-untranslated region of the mouse mammary tumor virus mRNA exhibits cap-independent translation initiation. Nucleic Acids Res 2010; 38:618-32. [PMID: 19889724 PMCID: PMC2811009 DOI: 10.1093/nar/gkp890] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 09/19/2009] [Accepted: 10/05/2009] [Indexed: 01/04/2023] Open
Abstract
In this study, we demonstrate the identification of an internal ribosome entry site (IRES) within the 5'-untranslated region (5'-UTR) of the mouse mammary tumor virus (MMTV). The 5'-UTR of the full-length mRNA derived from the infectious, complete MMTV genome was cloned into a dual luciferase reporter construct containing an upstream Renilla luciferase gene (RLuc) and a downstream firefly luciferase gene (FLuc). In rabbit reticulocyte lysate, the MMTV 5'-UTR was capable of driving translation of the second cistron. In vitro translational activity from the MMTV 5'-UTR was resistant to the addition of m(7)GpppG cap-analog and cleavage of eIF4G by foot-and-mouth disease virus (FMDV) L-protease. IRES activity was also demonstrated in the Xenopus laevis oocyte by micro-injection of capped and polyadenylated bicistronic RNAs harboring the MMTV-5'-UTR. Finally, transfection assays showed that the MMTV-IRES exhibits cell type-dependent translational activity, suggesting a requirement for as yet unidentified cellular factors for its optimal function.
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Affiliation(s)
- Maricarmen Vallejos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Pablo Ramdohr
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Fernando Valiente-Echeverría
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Karla Tapia
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Felipe E. Rodriguez
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Fernando Lowy
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - J. Pablo Huidobro-Toro
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - John A. Dangerfield
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Pontificia Universidad Católica de Chile, Marcoleta 391, Centro de Regulación Celular y Patología, J. V. Luco e Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile and Institute of Virology, University of Veterinary Sciences, Veterinaerplatz 1, A-1210 Vienna, Austria and Christian Doppler Laboratory Foreign Module for Virology-Nanotechnology, #05-518 Centros, 20 Biopolis Way, 138668 Singapore
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