The Secret Life of the Inhibitor of Virus Replication

Viruses. 2022 Dec 14;14(12):2782. doi: 10.3390/v14122782.

Abstract

The inhibitor of virus replication (IVR) is an inducible protein that is not virus-target-specific and can be induced by several viruses. The GenBank was interrogated for sequences closely related to the tobacco IVR. Various RNA fragments from tobacco, tomato, and potato and their genomic DNA contained IVR-like sequences. However, IVRs were part of larger proteins encoded by these genomic DNA sequences, which were identified in Arabidopsis as being related to the cyclosome protein designated anaphase-promoting complex 7 (APC7). Sequence analysis of the putative APC7s of nine plant species showed proteins of 558-561 amino acids highly conserved in sequence containing at least six protein-binding elements of 34 amino acids called tetratricopeptide repeats (TPRs), which form helix-turn-helix structures. The structures of Arabidopsis APC7 and the tobacco IVR proteins were modeled using the AlphaFold program and superimposed, showing that IVR had the same structure as the C-terminal 34% of APC7, indicating that IVR was a product of the APC7 gene. Based on the presence of various transcription factor binding sites in the APC7 sequences upstream of the IVR coding sequences, we propose that IVR could be expressed by these APC7 gene sequences involving the transcription factor SHE1.

Keywords: Arabidopsis; anaphase-promoting complex 7; cyclosome; defense response factors; inhibitor of virus replication; protein structures; solanaceous; tobacco.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids
  • Anaphase-Promoting Complex-Cyclosome
  • Apc7 Subunit, Anaphase-Promoting Complex-Cyclosome / chemistry
  • Apc7 Subunit, Anaphase-Promoting Complex-Cyclosome / metabolism
  • Arabidopsis Proteins*
  • Arabidopsis* / metabolism
  • N-Acetylglucosaminyltransferases
  • Transcription Factors
  • Virus Replication

Substances

  • Apc7 Subunit, Anaphase-Promoting Complex-Cyclosome
  • Anaphase-Promoting Complex-Cyclosome
  • Amino Acids
  • Transcription Factors
  • SECRET AGENT protein, Arabidopsis
  • N-Acetylglucosaminyltransferases
  • Arabidopsis Proteins

Grants and funding

This study was supported in part by grant number 32003533HD020 (to P.P.) from the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET); and in part by a grant from IPET (to J.-Y.Y.) through the Agriculture, Food and Rural Affairs Convergence Technologies Program for Educating Creative Global Leader Program, funded by the Ministry of Agriculture, Food and Rural Affairs (MAFRA) (321001–03). M.A. acknowledges financial support from Tarbiat Modares University. E.B. was supported by a postdoctoral fellowship from the NRF of the Republic of Korea (NRF-2019R1A6A3A03032528).