Free initiation factors eIF4A and eIF4B are dispensable for translation initiation on uncapped mRNAs
- 46 Downloads
The formation of ribosomal 48S initiation complexes at the start AUG codon of uncapped mRNA leader sequences was studied using the methodology of primer extension inhibition (toe-printing). The experiments were performed in the system composed of purified individual components required for translation initiation. The formation of ribosomal 48S initiation complexes at the initiation codon was tested depending on the presence of the initiation factors eIF4F, eIF4A, and eIF4B. Several mRNAs containing short leader sequences lacking the extended secondary structure were studied. It was found that 48S ribosomal complexes at mRNAs with such leaders were not formed in the absence of eIF4F. In contrast, the removal of either eIF4A or eIF4B from the experimental system was found to be dispensable for the formation of the 48S complex.
Key wordstranslation initiation 48S ribosomal initiation complex initiation factors eIF4F eIF4A eIF4B toe-printing
Unable to display preview. Download preview PDF.
- 10.Dmitriev, S. E., Terenin, I. M., Dunaevsky, Y. E., Merrick, W. C., and Shatsky, I. N. (2003) Assembly of 48S translation initiation complexes from purified components with mRNAs that have some base pairing within their 5′-untranslated regions, Mol. Cell. Biol., 23, 8925–8933.CrossRefPubMedPubMedCentralGoogle Scholar
- 13.Agalarov, S. Ch., Sakharov, P. A., Fattakhova, D. Kh., Sogorin, E. A., and Spirin, A. S. (2014) Internal translation initiation and eIF4F/ATP-independent scanning of mRNA by eukaryotic ribosomal particles, Sci. Rep., 4, doi: 10.1038/srep04438.Google Scholar
- 14.Agalarov, S. C., Sogorin, E. A., Shirokikh, N. E., and Spirin, A. S. (2011) Insight into the structural organization of the omega leader of TMV RNA: the role of various regions of the sequence in the formation of a compact structure of the omega RNA, Biochem. Biophys. Res. Commun., 404, 250–253.CrossRefPubMedGoogle Scholar
- 25.Svitkin, Y. V., Pause, A., Haghighat, A., Pyronnet, S., Witherell, G., Belsham, G. J., and Sonenberg, N. (2001) The requirement for eukaryotic initiation factor 4A (elF4A) in translation is in direct proportion to the degree of mRNA 5′-secondary structure, RNA, 7, 382–394.CrossRefPubMedPubMedCentralGoogle Scholar