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Regulated ribosomal frameshifting by an RNA-protein interaction
H Kollmus1, M W Hentze, H Hauser
1Genetics of Eukaryotes, GBF Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, Germany.
RNA (New York, N.Y.)
|April 1, 1996
Summary
Ribosomal frameshifting, crucial for retroviral replication, can be reversibly controlled by mRNA-binding proteins. Replacing a viral RNA hairpin with an iron-responsive element demonstrated protein-dependent frameshifting regulation.
Area of Science:
- Molecular Biology
- Virology
- Gene Regulation
Background:
- Ribosomal frameshifting is a key translational mechanism in retroviral replication.
- It involves a slippery sequence and a downstream RNA structure enhancer.
- The precise function of RNA structures and potential protein regulation remains unclear.
Purpose of the Study:
- To investigate the role of mRNA-binding proteins in regulating retroviral ribosomal frameshifting.
- To determine if protein binding to RNA structures can modulate frameshifting efficiency.
- To explore alternative RNA structures for controlling frameshifting.
Main Methods:
- Replaced the HIV-1 gag-pol frameshift RNA hairpin with the iron-responsive element (IRE) from ferritin mRNA.
- Utilized a lacZ/luciferase reporter construct in transfected BHK-21 cells.
- Treated cells with an iron chelator (desferrioxamine) to modulate iron regulatory protein (IRP) binding to IRE.
Main Results:
- The IRE, and a mutated version unable to bind IRPs, functionally substituted for the HIV-1 hairpin.
- Iron regulatory protein binding to the wild-type IRE specifically and strongly augmented frameshift activity.
- Frameshifting efficiency was modulated by protein binding in an iron-dependent manner.
Conclusions:
- Demonstrates that ribosomal frameshifting can be regulated by specific mRNA-binding proteins.
- Establishes a mechanism for reversible, protein-dependent control of frameshifting.
- Highlights the potential of using RNA-binding proteins to modulate viral replication strategies.