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Structural and functional diversity of viral IRESes
Laurent Balvay1, Ricardo Soto Rifo, Emiliano P Ricci
1Unité de Virologie Humaine, Ecole Normale Supérieure de Lyon, Lyon F-693643, France.
Biochimica Et Biophysica Acta
|July 28, 2009
Summary
Internal Ribosome Entry Site (IRES) elements enable cap-independent translation of viral RNA. This review compares IRES structure and function across four distinct viral families, highlighting their role in translation initiation.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Picornavirus RNA translation revealed a cap-independent initiation mechanism.
- Internal Ribosome Entry Site (IRES) elements facilitate direct ribosome binding to the 5' UTR.
- IRES elements enable translation of mRNA lacking a 5' cap structure.
Purpose of the Study:
- To compare and contrast the structure and function of IRES elements.
- To investigate IRES elements across four distinct viral families.
- To understand the role of IRES in viral translation.
Main Methods:
- Utilized bicistronic vectors to demonstrate cap-independent translation.
- Analyzed IRES elements from Picornaviruses, Flaviviruses, Dicistroviruses, and Lentiviruses.
- Reviewed existing literature on IRES structure and function.
Main Results:
- IRES elements were found in multiple viral families, conferring a selective advantage.
- IRES elements allow ribosome recruitment when cap-dependent synthesis is repressed.
- Demonstrated the ability of PV and EMCV 5' UTRs to bind the 43S preinitiation complex.
Conclusions:
- IRES elements are crucial for viral RNA translation initiation in a cap-independent manner.
- The diverse families of RNA viruses utilize IRES elements for translation regulation.
- IRES-mediated translation provides a survival advantage under host stress conditions.
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