Name
RNA Chaperone and Helix Destabilizing Activity of Mal de Río Cuarto Virus P9-1 Protein
Presenter
Demian Monti, Institute of Agricultural Technology (INTA)
Co-Author(s)
Monti, D1; Chakraborty, J2; Kaundal, S2; Thachangattuthodi, A2; Parreño, V1,3; del Vas, M3,4; Prasad, BVV2
1 INCUINTA, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas (CICVyA), Instituto Nacional de Tecnología Agropecuaria (INTA), Hurlingham, Buenos Aires, Argentina
2 Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
3 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires, Argentina
4 Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Hurlingham, Buenos Aires, Argentina
Abstract Category
Virus Replication: Entry, Exit and Everything in Between
Abstract
Double-stranded RNA (dsRNA) viruses encode proteins that facilitate RNA synthesis and genome replication, often by acting as RNA chaperones. P9-1, a non-structural protein from Mal de Río Cuarto virus (MRCV, Fijivirus genus, Spinareoviridae family), is a key component of viral replication factories and is shown to bind RNA, leading to increased ATPase activity. Here, we demonstrate that P9-1 exhibits RNA chaperone activity, promoting the annealing and rearrangement of RNA structures, and possesses helix-destabilizing activity, facilitating local strand separation. These activities are strictly dependent on Mg²⁺, suggesting a role in modulating RNA conformation during viral replication.
To further investigate the structural basis of these functions, we analyzed a C-terminal deletion mutant of P9-1, lacking its 24 C-terminal amino acids. Remarkably, this mutant was unable to destabilize RNA duplexes or exhibit RNA chaperone activity, indicating that the C-terminal region is essential for RNA remodeling. Given that the full-length P9-1 assembles into decameric structures, while the mutant adopts a dimeric form, these results suggest that higher-order assembly may be required for its chaperone function.
Our findings provide the first evidence of RNA chaperone and helix destabilizing activity in a Fijivirus non-structural protein and highlight P9-1 as a potential target for antiviral strategies. Further studies will focus on elucidating the molecular interactions between P9-1 and viral RNA, contributing to a better understanding of RNA remodeling mechanisms in dsRNA viruses.
To further investigate the structural basis of these functions, we analyzed a C-terminal deletion mutant of P9-1, lacking its 24 C-terminal amino acids. Remarkably, this mutant was unable to destabilize RNA duplexes or exhibit RNA chaperone activity, indicating that the C-terminal region is essential for RNA remodeling. Given that the full-length P9-1 assembles into decameric structures, while the mutant adopts a dimeric form, these results suggest that higher-order assembly may be required for its chaperone function.
Our findings provide the first evidence of RNA chaperone and helix destabilizing activity in a Fijivirus non-structural protein and highlight P9-1 as a potential target for antiviral strategies. Further studies will focus on elucidating the molecular interactions between P9-1 and viral RNA, contributing to a better understanding of RNA remodeling mechanisms in dsRNA viruses.