Previous Article | Next Article ![]()
J. Virol., 11 1997, 8330-8339, Vol 71, No. 11
M Niepmann, A Petersen, K Meyer and E Beck
The synthesis of picornavirus polyproteins is initiated cap independently
far downstream from the 5' end of the viral RNA at the internal ribosome
entry site (IRES). The cellular polypyrimidine tract- binding protein (PTB)
binds to the IRES of foot-and-mouth disease virus (FMDV). In this study, we
demonstrate that PTB is a component of 48S and 80S ribosomal initiation
complexes formed with FMDV IRES RNA. The incorporation of PTB into these
initiation complexes is dependent on the entry of the IRES RNA, since PTB
and IRES RNA can be enriched in parallel either in 48S or 80S ribosomal
complexes by stage-specific inhibitors of translation initiation. The
formation of the ribosomal initiation complexes with the IRES occurs
slowly, is temperature dependent, and correlates with the incorporation of
PTB into these complexes. In a first step, PTB binds to the IRES, and then
the small ribosomal subunit encounters this PTB-IRES complex. Mutations in
the major PTB-binding site interfere simultaneously with the formation of
initiation complexes, translation efficiency, and PTB cross-linking. PTB
stimulates translation directed by the FMDV IRES in a rabbit reticulocyte
lysate depleted of internal PTB, and the efficiency of translation can be
restored to the original level by the addition of PTB. These results
indicate that PTB plays an important role in the formation of initiation
complexes with FMDV IRES RNA and in stimulation of internal translation
initiation with this picornavirus.
Copyright © 1997, American Society for Microbiology
Functional involvement of polypyrimidine tract-binding protein in translation initiation complexes with the internal ribosome entry site of foot-and-mouth disease virus
Institut fur Biochemie, Giessen, Germany. michael.niepmann@biochemie.med.uni-giessen.de
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|