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Using viral species specificity to define a critical protein/RNA interaction surface
G A Coburn1, H L Wiegand, Y Kang
1Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
Genes & Development
|May 19, 2001
Summary
A single amino acid change in the Tap protein allows it to bind and export messenger RNA (mRNA) containing the constitutive transport element (CTE) across species. This finding highlights the importance of cross-species complementation for studying viral replication factors.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- The Tap protein is crucial for mRNA export from the nucleus, including export mediated by the constitutive transport element (CTE).
- CTE function exhibits species specificity, working in human but not quail cells.
Purpose of the Study:
- To investigate the molecular basis for the species-specific interaction between the Tap protein and the CTE.
- To identify the specific region and residues within the Tap protein responsible for CTE binding and function.
Main Methods:
- Cross-species genetic complementation assays using human and quail Tap proteins.
- Site-directed mutagenesis to alter specific amino acid residues in the quail Tap protein.
- Analysis of mRNA export activity and direct binding assays.
Main Results:
- Quail Tap protein fails to support CTE function due to an inability to bind the CTE.
- A single amino acid substitution (glutamine 246 to arginine) in quail Tap restores both CTE binding and function.
- This critical residue is located on an exterior surface of the Tap protein, defining a key CTE-binding site.
Conclusions:
- A specific residue on the Tap protein is essential for mediating CTE binding and function.
- Cross-species genetic complementation is a powerful tool for dissecting the roles of cellular factors in viral replication.
- Understanding Tap-CTE interactions provides insights into nuclear export mechanisms and viral strategies.