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Intercistronic region required for polycistronic pre-mRNA processing in Caenorhabditis elegans
T Huang1, S Kuersten, A M Deshpande
1Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
Molecular and Cellular Biology
|February 7, 2001
Summary
In C. elegans, a U-rich element downstream of gene gpd-2 is crucial for processing polycistronic pre-mRNAs. This element specifically directs trans-splicing to downstream gene gpd-3, ensuring proper mRNA biosynthesis.
Area of Science:
- Molecular Biology
- Genetics
- RNA Processing
Background:
- Polycistronic pre-mRNAs in C. elegans are processed via 3' end cleavage/polyadenylation and trans-splicing.
- Previous work suggested a link between these events for heat shock-induced gpd-2-gpd-3 pre-mRNA.
Purpose of the Study:
- To investigate the role of the intercistronic region in gpd-2-gpd-3 polycistronic pre-mRNA processing.
- To identify sequences regulating 3'-end formation and trans-splicing.
Main Methods:
- Linker scan mutational analysis of the intercistronic region.
- Transplantation of identified elements to heterologous contexts.
- Assessment of mRNA accumulation and trans-splicing specificity.
Main Results:
- No sequences downstream of the 3' end were critical for 3'-end formation.
- A U-rich (Ur) element, 29 bp downstream of the 3' end, is essential for downstream mRNA biosynthesis.
- This Ur element alone mediates SL2 trans-splicing and mRNA accumulation, even in a heterologous gene context.
Conclusions:
- The Ur element is a key cis-acting signal for downstream mRNA processing in polycistronic transcripts.
- This element appears to be the primary determinant for SL2 trans-splicing specificity.
- The findings provide insights into the mechanisms of polycistronic gene expression regulation.
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