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UV-dependent alternative splicing uncouples p53 activity and PIG3 gene function through rapid proteolytic degradation
Chris D Nicholls1, Michael A Shields, Patrick W K Lee
1Cancer Biology Research Group, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
The Journal of Biological Chemistry
|April 7, 2004
Summary
Researchers discovered a new PIG3 alternative splice (PIG3AS) product. This UV-inducible splicing event alters protein degradation, uncoupling p53 activity from PIG3 gene activation during DNA damage response.
Area of Science:
- Molecular Biology
- Cellular Biology
- Genetics
Background:
- The p53-inducible gene 3 (PIG3) is a known transcriptional target of the tumor suppressor p53, implicated in apoptosis.
- Understanding the regulation of PIG3 expression and its role in cellular responses to DNA damage is crucial.
Purpose of the Study:
- To identify and characterize novel alternatively spliced products of the PIG3 gene.
- To investigate the role of alternative splicing in the cellular DNA damage response, particularly in response to UV radiation.
Main Methods:
- Analysis of PIG3 gene transcripts and protein products using molecular biology techniques.
- Investigating pre-mRNA splicing patterns under various cellular conditions, including UV irradiation.
- Assessing protein stability and degradation pathways, including proteasome inhibition.
Main Results:
- Identification of a novel PIG3 alternative splice product, PIG3AS, arising from exon skipping.
- Demonstration that UV light dramatically shifts PIG3 pre-mRNA splicing towards PIG3AS production.
- PIG3AS protein exhibits rapid degradation, which is reversible by proteasome inhibition, unlike the PIG3 protein.
Conclusions:
- This study presents the first example of an endogenous, UV-inducible alternative splicing event.
- Control of splicing machinery is integral to the cellular DNA damage response.
- Rapid proteolytic degradation of PIG3AS provides a mechanism to decouple p53 activity from PIG3 gene activation, independent of promoter control.