A Capsid Protein Fragment of a Fusagra-like Virus Found in Carica papaya Latex Interacts with the 50S Ribosomal Protein L17

Viruses. 2023 Feb 15;15(2):541. doi: 10.3390/v15020541.

Abstract

Papaya sticky disease is caused by the association of a fusagra-like and an umbra-like virus, named papaya meleira virus (PMeV) and papaya meleira virus 2 (PMeV2), respectively. Both viral genomes are encapsidated in particles formed by the PMeV ORF1 product, which has the potential to encode a protein with 1563 amino acids (aa). However, the structural components of the viral capsid are unknown. To characterize the structural proteins of PMeV and PMeV2, virions were purified from Carica papaya latex. SDS-PAGE analysis of purified virus revealed two major proteins of ~40 kDa and ~55 kDa. Amino-terminal sequencing of the ~55 kDa protein and LC-MS/MS of purified virions indicated that this protein starts at aa 263 of the deduced ORF1 product as a result of either degradation or proteolytic processing. A yeast two-hybrid assay was used to identify Arabidopsis proteins interacting with two PMeV ORF1 product fragments (aa 321-670 and 961-1200). The 50S ribosomal protein L17 (AtRPL17) was identified as potentially associated with modulated translation-related proteins. In plant cells, AtRPL17 co-localized and interacted with the PMeV ORF1 fragments. These findings support the hypothesis that the interaction between PMeV/PMeV2 structural proteins and RPL17 is important for virus-host interactions.

Keywords: Totiviridae; coat protein; dsRNA; fusagra-like virus; plant virus; protein–protein interaction.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids
  • Capsid
  • Capsid Proteins* / genetics
  • Carica*
  • Chromatography, Liquid
  • Latex
  • RNA Viruses / genetics
  • Tandem Mass Spectrometry

Substances

  • Amino Acids
  • Capsid Proteins
  • Latex
  • ribosomal protein L17

Grants and funding

This research was funded by Fundação de Amparo à Pesquisa do Espírito Santo—FAPES/PRONEX grant number: 80.598.609 and FAPES/SEAG grant number: 2020-XVOM5 to JAV and PMBF. Research at North Carolina State University was supported, in part, by the United States Department of Agriculture—National Institute of Food and Agriculture (USDA-NIFA) grant 2016-67013-27492 and USDA Floriculture and Nursery Research Initiative (USDA-FNRI) grant 6034-22000-039-06S. JAV, FMZ, and PMBF acknowledge the Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq for their research productivity award (307905/2020-9; 312493/2018-5; 308306/2021). PMBF also acknowledges FAPES grant number: 269.