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The splicing factor PRP2, a putative RNA helicase, interacts directly with pre-mRNA
S Teigelkamp1, M McGarvey, M Plumpton
1Institute of Cell and Molecular Biology, University of Edinburgh, UK.
The EMBO Journal
|February 15, 1994
Summary
The splicing factor PRP2 (primate splicing factor 2) binds directly to pre-mRNA within spliceosomes. ATP hydrolysis, stimulated by pre-mRNA, is necessary for PRP2 release, suggesting pre-mRNA is the target of its RNA helicase activity.
Area of Science:
- Molecular Biology
- RNA Splicing Mechanisms
- Protein-RNA Interactions
Background:
- The splicing factor PRP2 is essential for pre-mRNA splicing but interacts transiently with spliceosomes, hindering detailed analysis.
- Understanding PRP2's role requires elucidating its interactions with spliceosomal components and RNA.
Purpose of the Study:
- To investigate the direct interactions between PRP2 protein and pre-mRNA within spliceosomes.
- To determine the role of ATP binding and hydrolysis in PRP2-pre-mRNA interactions and release.
Main Methods:
- Utilized a dominant-negative PRP2 mutant to stabilize spliceosomes and analyzed interactions via UV-crosslinking.
- Employed ATP-depleted spliceosomes and compared ATP vs. gamma S-ATP binding to assess ATP's role.
- Tested interactions with various mutant and truncated pre-mRNAs.
Main Results:
- A dominant-negative PRP2 mutant directly binds to pre-mRNA in an assembled spliceosome, independent of the 3' splice site.
- PRP2 interacts with pre-mRNA in an ATP-independent manner, but ATP hydrolysis, not binding, is required for its release.
- Pre-mRNA acts as a co-factor stimulating PRP2's ATP hydrolysis.
Conclusions:
- Pre-mRNA is the direct target of PRP2's RNA helicase activity, facilitating RNA displacement.
- PRP2's ATP hydrolysis, stimulated by pre-mRNA, is crucial for promoting the first step of splicing.