Browsing by Author "Pino, Karla"

Now showing 1 - 4 of 4
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    A cis-Acting Element Present within the gag Open Reading Frame Negatively Impacts on the Activity of the HIV-1 IRES
    (2013) Valiente Echeverria, Fernando; Vallejos, Maricarmen; Monette, Anne; Pino, Karla; Letelier, Alejandro; Huidobro Toro, J. Pablo; Mouland, Andrew J.; López Lastra, Marcelo Andrés
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    Detection of high biliary and fecal viral loads in patients with chronic hepatitis C virus infection
    (2017) Monrroy Bravo, Hugo Alfonso; Angulo, J.; Pino, Karla; Labbé, P.; Miquel P., Juan Francisco; López Lastra, Marcelo Andrés; Soza, Alejandro
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    Structural domains within the HIV-1 mRNA. and the ribosomal protein S25 influence cap-independent translation initiation
    (2016) Carvajal, Felipe; Vallejos, Maricarmen; Walters, Beth; Contreras, Nataly; Hertz, Marla I.; Olivares, Eduardo; Cáceres, Carlos J.; Pino, Karla; Letelier, Alejandro; López Lastra, Marcelo Andrés; Thompson, Sunnie R.
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    The double-stranded RNA-binding protein, Staufen1 is an IRES-transacting factor regulating HIV-1 cap-independent translation initiation
    (2022) Ramos, Hade; Monette, Anne; Niu, Meijuan; Barrera, Aldo; Lopez-Ulloa, Brenda; Fuentes, Yazmin; Guizar, Paola; Pino, Karla; DesGroseillers, Luc; Mouland, Andrew J.; Lopez-Lastra, Marcelo
    Translation initiation of the viral genomic mRNA (vRNA) of human immunodeficiency virus-type 1 (HIV-1) can be mediated by a cap- or an internal ribosome entry site (IRES)-dependent mechanism. A previous report shows that Staufen1, a cellular double-stranded (ds) RNA-binding protein (RBP), binds to the 5'untranslated region (5'UTR) of the HIV-1 vRNA and promotes its cap-dependent translation. In this study, we now evaluate the role of Staufen1 as an HIV-1 IRES-transacting factor (ITAF). We first confirm that Staufen1 associates with both the HIV-1 vRNA and the Gag protein during HIV-1 replication. We found that in HIV-1-expressing cells, siRNA-mediated depletion of Staufen1 reduces HIV-1 vRNA translation. Using dual-luciferase bicistronic mRNAs, we show that the siRNA-mediated depletion and cDNA-mediated overexpression of Staufen1 acutely regulates HIV-1 IRES activity. Furthermore, we show that Staufenl-vRNA interaction is required for the enhancement of HIV-1 IRES activity. Interestingly, we find that only Staufen1 harboring an intact dsRNA-binding domain 3 (dsRBD3) rescues HIV-1 IRES activity in Staufen1 CRISPR-Cas9 gene edited cells. Finally, we show that the expression of Staufen1-dsRBD3 alone enhances HIV-1 IRES activity. This study provides evidence of a novel role for Staufen1 as an ITAF promoting HIV-1 vRNA IRES activity.