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Translational frameshifting mediated by a viral sequence in plant cells
1Plant Pathology Department, Iowa State University, Ames 50011.
Summary
Plant viruses like barley yellow dwarf virus use ribosomal frameshifting to express their polymerase genes. This translation mechanism, observed at approximately 1% efficiency, is crucial for viral gene expression in plants.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- The expression of viral polymerase genes is often complex.
- Ribosomal frameshifting is a known mechanism for viral gene expression in various hosts.
- Barley yellow dwarf virus (BYDV) polymerase gene expression was hypothesized to involve frameshifting.
Purpose of the Study:
- To investigate the mechanism of polymerase gene expression in barley yellow dwarf virus (BYDV).
- To determine if ribosomal frameshifting occurs during BYDV translation.
- To characterize the sequences involved in potential BYDV frameshifting.
Main Methods:
- Constructed plasmids containing BYDV genomic RNA sequences spanning the overlap region between polymerase and upstream genes.
- Introduced these constructs into plant cells to assess reporter gene expression, dependent on a -1 frameshift event.
- Mutated the stop codon of the upstream open reading frame and analyzed the effect on frameshifting.
Main Results:
- Detected a ribosomal frameshifting event at approximately 1% efficiency in plant cells.
- Frameshifting was abolished by deleting the stop codon of the upstream open reading frame.
- A predicted stem-loop structure upstream of the frameshift site was not essential for the event.
Conclusions:
- Plant viruses, including BYDV, can utilize ribosomal frameshifting for gene expression.
- The polymerase gene of BYDV is expressed via a -1 frameshift event.
- This mechanism is conserved across different viral kingdoms, highlighting its evolutionary significance.