Small Cysteine-Rich Proteins of Different Groups of Plant RNA Viruses Are Related to Different Families of Nucleic Acid-Binding Proteins

Virology. 1991 Mar;181(1):395-8. doi: 10.1016/0042-6822(91)90512-a.


The 3'-terminal genes in genomic RNAs of four groups of plant positive strand RNA viruses (hordei-, furo-, tobra-, and carlaviruses) encode small proteins enriched in Cys residues. The arrangement of Cys and in some cases also His residues in these proteins is compatible with finger formation. A computer-assisted sequence comparison of viral Cys-rich proteins reveals no significant similarity between them. It is shown that the hordeivirus Cys-rich protein (17K) is related to a group of chloroplast tRNA intron-encoded proteins, whereas the respective furovirus protein (14K) is similar to E6 proteins of papillomaviruses. Somewhat less significant similarity, marked, however, by conservation of a number of positively charged residues, was observed between the sequences of tobravirus Cys-rich proteins and the basic domains of high mobility group chromatin proteins. It can be speculated that plant RNA virus Cys-rich proteins bind RNA and/or DNA and might be involved in regulation of virus and/or host genome expression. In the course of evolution these virus proteins may have originated from different nucleic acid-binding proteins.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / genetics*
  • Cysteine*
  • Databases, Factual
  • Gene Expression Regulation, Viral
  • Humans
  • Introns
  • Molecular Sequence Data
  • Plant Viruses / genetics*
  • RNA Viruses / genetics*
  • RNA, Transfer / genetics
  • Sequence Homology, Nucleic Acid
  • Viral Proteins / genetics*


  • Carrier Proteins
  • Viral Proteins
  • RNA, Transfer
  • Cysteine