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Promoter elements in the influenza vRNA terminal structure
R Flick1, G Neumann, E Hoffmann
1Institut für Mikrobiologie und Molekularbiologie, Giessen, Germany.
RNA (New York, N.Y.)
|October 1, 1996
Summary
This study reveals the influenza vRNA promoter structure, detailing how its double-stranded RNA rod and nucleotide sequences interact with polymerase. The findings propose a "corkscrew model" for viral RNA promoter activation.
Area of Science:
- Virology
- Molecular Biology
- Structural Biology
Background:
- Influenza virus RNA (vRNA) terminal structures are crucial for viral replication.
- Understanding the promoter elements of vRNA is key to deciphering viral transcription mechanisms.
Purpose of the Study:
- To elucidate the role of specific vRNA terminal structures and nucleotide sequences as promoter signals in influenza virus replication.
- To investigate the functional contribution of different vRNA promoter elements and their interactions with the viral polymerase.
Main Methods:
- In vivo studies using nucleotide substitution and insertion derivatives of influenza vRNA.
- Analysis of intrastrand base pairing through complementary double exchanges.
- Mutagenesis studies of the promoter proximal element.
Main Results:
- A distal promoter element comprises a six-base pair double-stranded RNA rod with exchangeable base positions.
- The proximal promoter element consists of nine partially complementary nucleotides at the vRNA 5' and 3' ends.
- A bulged conformation is formed by a single unpaired nucleotide, with specific nucleotide interactions and a single-stranded tetra-loop identified.
Conclusions:
- The vRNA promoter structure involves distinct distal and proximal elements interacting with polymerase.
- A
- corkscrew model
- is proposed to describe the activated vRNA/polymerase interaction based on the three base-paired segments' conformation.