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The apoptosis-promoting factor TIA-1 is a regulator of alternative pre-mRNA splicing
1Gene Expression Programme European Molecular Biology Laboratory Meyerhofstrasse 1 D-69117, Heidelberg, Germany.
Abstract:
We report here that the apoptosis-promoting protein TIA-1 regulates alternative pre-mRNA splicing of the Drosophila melanogaster gene male-specific-lethal 2 and of the human apoptotic gene Fas. TIA-1 associates selectively with pre-mRNAs that contain 5' splice sites followed by U-rich sequences. TIA-1 binding to the U-rich stretches facilitates 5' splice site recognition by U1 snRNP. This activity is critical for activation of the weak 5' splice site of msl-2 and for modulating the choice of splice site partner in Fas. Structural and functional similarities with the Saccharomyces cerevisiae splicing factor Nam8 suggest striking evolutionary conservation of a mechanism of pre-mRNA splicing regulation that controls biological processes as diverse as meiosis in yeast, dosage compensation in fruit flies, or programmed cell death in humans.
Insights
The apoptosis-promoting protein TIA-1 controls gene splicing in fruit flies and humans. This protein binds to specific RNA sequences, aiding in crucial cellular processes like programmed cell death.
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- Alternative pre-mRNA splicing is a key mechanism for generating protein diversity.
- The regulation of splicing is crucial for normal cellular function and development.
- TIA-1 is known to be involved in RNA processing and apoptosis.
Purpose of the Study:
- To investigate the role of the apoptosis-promoting protein TIA-1 in alternative pre-mRNA splicing.
- To identify the specific pre-mRNAs regulated by TIA-1.
- To elucidate the mechanism by which TIA-1 influences splicing decisions.
Main Methods:
- Analysis of alternative splicing in Drosophila melanogaster (male-specific-lethal 2 gene) and human (Fas gene) models.
- RNA immunoprecipitation to identify TIA-1 binding sites on pre-mRNAs.
- Biochemical assays to assess the effect of TIA-1 on splice site recognition.
Main Results:
- TIA-1 regulates alternative splicing of the Drosophila msl-2 gene and the human Fas gene.
- TIA-1 selectively binds to pre-mRNAs containing U-rich sequences adjacent to 5' splice sites.
- TIA-1 binding enhances the recognition of weak 5' splice sites by U1 snRNP, impacting alternative splicing outcomes.
Conclusions:
- TIA-1 acts as a regulator of alternative pre-mRNA splicing through specific RNA sequence recognition.
- This splicing regulatory mechanism is conserved across species and involved in diverse biological processes including dosage compensation, meiosis, and apoptosis.
- The findings highlight a conserved role for RNA-binding proteins in controlling gene expression and biological outcomes.