The viral nucleocapsid protein and the human RNA-binding protein Mex3A promote translation of the Andes orthohantavirus small mRNA

Jorge Vera-Otarola; Estefania Castillo-Vargas; Jenniffer Angulo; Francisco M Barriga; Eduard Batlle; Marcelo Lopez-Lastra

doi:10.1371/journal.ppat.1009931

The viral nucleocapsid protein and the human RNA-binding protein Mex3A promote translation of the Andes orthohantavirus small mRNA

PLoS Pathog. 2021 Sep 21;17(9):e1009931. doi: 10.1371/journal.ppat.1009931. eCollection 2021 Sep.

Authors

Jorge Vera-Otarola^{1

2}, Estefania Castillo-Vargas^{1

3}, Jenniffer Angulo¹, Francisco M Barriga⁴, Eduard Batlle^{4

5

6}, Marcelo Lopez-Lastra¹

Affiliations

¹ Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
² Unidad de Virología Aplicada, Dirección de Investigación y Doctorados de la Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
³ Facultad de Odontología, Universidad Finis Terrae, Santiago, Chile.
⁴ Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology. Barcelona, Spain.
⁵ ICREA, Barcelona, Spain.
⁶ Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Barcelona, Spain.

Abstract

The capped Small segment mRNA (SmRNA) of the Andes orthohantavirus (ANDV) lacks a poly(A) tail. In this study, we characterize the mechanism driving ANDV-SmRNA translation. Results show that the ANDV-nucleocapsid protein (ANDV-N) promotes in vitro translation from capped mRNAs without replacing eukaryotic initiation factor (eIF) 4G. Using an RNA affinity chromatography approach followed by mass spectrometry, we identify the human RNA chaperone Mex3A (hMex3A) as a SmRNA-3'UTR binding protein. Results show that hMex3A enhances SmRNA translation in a 3'UTR dependent manner, either alone or when co-expressed with the ANDV-N. The ANDV-N and hMex3A proteins do not interact in cells, but both proteins interact with eIF4G. The hMex3A-eIF4G interaction showed to be independent of ANDV-infection or ANDV-N expression. Together, our observations suggest that translation of the ANDV SmRNA is enhanced by a 5'-3' end interaction, mediated by both viral and cellular proteins.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Gene Expression Regulation, Viral / physiology
Humans
Nucleocapsid Proteins / metabolism*
Orthohantavirus / genetics*
Phosphoproteins / metabolism*
Protein Biosynthesis / physiology*
RNA, Messenger / genetics
RNA, Viral / genetics*
RNA-Binding Proteins / metabolism*

Substances

MEX3A protein, human
Nucleocapsid Proteins
Phosphoproteins
RNA, Messenger
RNA, Viral
RNA-Binding Proteins

Grants and funding

The work was supported by the Agencia Nacional de Investigacion y Desarrollo (ANID), Gobierno de Chile though the Iniciativa Cientifica Milenio (ICM), Instituto Milenio de Inmunología e Inmunoterapia (P09/016-F; ICN09_016), Programa de Investigación Asociativa PIA-ACT1408 to MLL, and FONDECYT 11150611 to JV-O, and by the Centre National de la Recherche Scientifique (CNRS, France), through the Laboratoire International Associé (LIA) program granted to MLL. EC-V conducted this research in partial fulfillment of the requirements for a Ph.D., Doctorado en Ciencias Biológicas mención Microbiología y Genética Molecular, Microbiología, Facultad de Biología, Pontificia Universidad Católica de Chile, funded by FONDECYT doctoral fellowships 21090539 and 24121224. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.