Base-pairing between untranslated regions facilitates translation of uncapped, nonpolyadenylated viral RNA

Mol Cell. 2001 May;7(5):1103-9. doi: 10.1016/s1097-2765(01)00252-0.

Abstract

Translationally competent mRNAs form a closed loop via interaction of initiation factors with the 5' cap and poly(A) tail. However, many viral mRNAs lack a cap and/or a poly(A) tail. We show that an uncapped, nonpolyadenylated plant viral mRNA forms a closed loop by direct base-pairing (kissing) of a stem loop in the 3' untranslated region (UTR) with a stem loop in the 5' UTR. This allows a sequence in the 3' UTR to confer translation initiation at the 5'-proximal AUG. This base-pairing is also required for replication. Unlike other cap-independent translation mechanisms, the ribosome enters at the 5' end of the mRNA. This remarkably long-distance base-pairing reveals a novel mechanism of cap-independent translation and means by which mRNA UTRs can communicate.

Publication types

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

MeSH terms

  • 3' Untranslated Regions / metabolism*
  • 5' Untranslated Regions / metabolism*
  • Amino Acid Sequence
  • Base Pairing*
  • Conserved Sequence
  • Luteovirus / genetics
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nucleic Acid Conformation
  • Poly A / genetics*
  • Protein Biosynthesis*
  • RNA, Messenger / chemistry
  • RNA, Messenger / genetics
  • RNA, Viral / chemistry
  • RNA, Viral / genetics*
  • RNA, Viral / metabolism
  • Ribosomes / metabolism
  • Sequence Alignment

Substances

  • 3' Untranslated Regions
  • 5' Untranslated Regions
  • RNA, Messenger
  • RNA, Viral
  • Poly A