Browsing by Author "Mendonca, Dafne"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Heterogeneous nuclear ribonucleoprotein K promotes cap-independent translation initiation of retroviral mRNAs
    (2024) Fuentes, Yazmin; Olguin, Valeria; Lopez-Ulloa, Brenda; Mendonca, Dafne; Ramos, Hade; Abdalla, Ana Luiza; Guajardo-Contreras, Gabriel; Niu, Meijuan; Rojas-Araya, Barbara; Mouland, Andrew J.; Lopez-Lastra, Marcelo
    Translation initiation of the human immunodeficiency virus-type 1 (HIV-1) genomic mRNA (vRNA) is cap-dependent or mediated by an internal ribosome entry site (IRES). The HIV-1 IRES requires IRES-transacting factors (ITAFs) for function. In this study, we evaluated the role of the heterogeneous nuclear ribonucleoprotein K (hnRNPK) as a potential ITAF for the HIV-1 IRES. In HIV-1-expressing cells, the depletion of hnRNPK reduced HIV-1 vRNA translation. Furthermore, both the depletion and overexpression of hnRNPK modulated HIV-1 IRES activity. Phosphorylations and protein arginine methyltransferase 1 (PRMT1)-induced asymmetrical dimethylation (aDMA) of hnRNPK strongly impacted the protein's ability to promote the activity of the HIV-1 IRES. We also show that hnRNPK acts as an ITAF for the human T cell lymphotropic virus-type 1 (HTLV-1) IRES, present in the 5 ' UTR of the viral sense mRNA, but not for the IRES present in the antisense spliced transcript encoding the HTLV-1 basic leucine zipper protein (sHBZ). This study provides evidence for a novel role of the host hnRNPK as an ITAF that stimulates IRES-mediated translation initiation for the retroviruses HIV-1 and HTLV-1.