Back to Search
Start Over
Global shape mimicry of tRNA within a viral internal ribosome entry site mediates translational reading frame selection.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America . 11/24/2015, Vol. 112 Issue 47, pE6446-E6455. 10p. - Publication Year :
- 2015
-
Abstract
- The dicistrovirus intergenic region internal ribosome entry site (IRES) adopts a triple-pseudoknotted RNA structure and occupies the core ribosomal E, P, and A sites to directly recruit the ribosome and initiate translation at a non-AUG codon. A subset of dicistrovirus IRESs directs translation in the 0 and +1 frames to produce the viral structural proteins and a +1 overlapping open reading frame called ORFx, respectively. Here we show that specific mutations of two unpaired adenosines located at the core of the three-helical junction of the honey bee dicistrovirus Israeli acute paralysis virus (IAPV) IRES PKI domain can uncouple 0 and +1 frame translation, suggesting that the structure adopts distinct conformations that contribute to 0 or +1 frame translation. Using a reconstituted translation system, we show that ribosomes assembled on mutant IRESs that direct exclusive 0 or +1 frame translation lack reading frame fidelity. Finally, a nuclear magnetic resonance/small-angle X-ray scattering hybrid approach reveals that the PKI domain of the IAPV IRES adopts an RNA structure that resembles a complete tRNA. The tRNA shape-mimicry enables the viral IRES to gain access to the ribosome tRNA-binding sites and form intermolecular contacts with the ribosome that are necessary for initiating IRES translation in a specific reading frame. [ABSTRACT FROM AUTHOR]
- Subjects :
- *RIBOSOMES
*TRANSFER RNA genetics
*GENETIC code
*HONEYBEE genetics
*ADENOSINES
Subjects
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 112
- Issue :
- 47
- Database :
- Academic Search Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 111199856
- Full Text :
- https://doi.org/10.1073/pnas.1512088112