Virus-specific capping of tobacco mosaic virus RNA: methylation of GTP prior to formation of covalent complex p126-m7GMP

FEBS Lett. 1999 Jul 16;455(1-2):45-8. doi: 10.1016/s0014-5793(99)00856-x.

Abstract

In capping cellular mRNAs, a covalent GMP-enzyme intermediate leads to formation of G(5')ppp(5')N at the 5' end of the RNA, which is modified by methylation catalyzed by guanine-7-methyltransferase. Here we show that isolated membranes from tobacco mosaic virus (TMV)-infected plant or insect cells expressing TMV replicase protein p126, synthesized m7GTP using S-adenosylmethionine (AdoMet) as the methyl donor, and catalyzed the formation of a covalent guanylate-p126 complex in the presence of AdoMet. The methyl group from AdoMet was incorporated into p126, suggesting that the complex consisted of m7GMP-p126. Thus, TMV and alphaviruses, despite their evolutionary distance, share the same virus-specific capping mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • DNA Primers
  • Guanosine Monophosphate / metabolism*
  • Guanosine Triphosphate / metabolism*
  • Insecta
  • Methylation
  • Methyltransferases / metabolism
  • Molecular Sequence Data
  • Nucleotidyltransferases / metabolism
  • Point Mutation
  • RNA Caps*
  • RNA, Viral / genetics*
  • RNA, Viral / metabolism
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Tobacco Mosaic Virus / genetics*

Substances

  • DNA Primers
  • RNA Caps
  • RNA, Viral
  • Recombinant Proteins
  • Guanosine Monophosphate
  • Guanosine Triphosphate
  • Methyltransferases
  • Nucleotidyltransferases