Related Experiment Video
Updated: Jun 13, 2026

A Reporter Assay to Analyze Intronic microRNA Maturation in Mammalian Cells
Published on: June 16, 2022
Degradation of YRA1 Pre-mRNA in the cytoplasm requires translational repression, multiple modular intronic elements,
Shuyun Dong1, Allan Jacobson, Feng He
1Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.
Abstract:
Intron-containing pre-mRNAs are normally retained and processed in the nucleus but are sometimes exported to the cytoplasm and degraded by the nonsense-mediated mRNA decay (NMD) pathway as a consequence of their inclusion of intronic in-frame termination codons. When shunted to the cytoplasm by autoregulated nuclear export, the intron-containing yeast YRA1 pre-mRNA evades NMD and is targeted by a cytoplasmic decay pathway mediated by the decapping activator Edc3p. Here, we have elucidated this transcript-specific decay mechanism, showing that Edc3p-mediated YRA1 pre-mRNA degradation occurs independently of translation and is controlled through five structurally distinct but functionally interdependent modular elements in the YRA1 intron. Two of these elements target the pre-mRNA as an Edc3p substrate and the other three mediate transcript-specific translational repression. Translational repression of YRA1 pre-mRNA also requires the heterodimeric Mex67p/Mtr2p general mRNA export receptor, but not Edc3p, and serves to enhance Edc3p substrate specificity by inhibiting the susceptibility of this pre-mRNA to NMD. Collectively, our data indicate that YRA1 pre-mRNA degradation is a highly regulated process that proceeds through translational repression, substrate recognition by Edc3p, recruitment of the Dcp1p/Dcp2p decapping enzyme, and activation of decapping.
Insights
Yeast YRA1 pre-mRNA uses a unique cytoplasmic decay pathway involving Edc3p, independent of translation. This process involves specific intronic elements for Edc3p targeting and translational repression, preventing nonsense-mediated decay.
Area of Science:
- Molecular Biology
- RNA Metabolism
- Gene Regulation
Background:
- Intron-containing pre-mRNAs are typically nuclear-processed but can be exported to the cytoplasm.
- Nonsense-mediated mRNA decay (NMD) degrades cytoplasmic pre-mRNAs with premature termination codons.
- Yeast YRA1 pre-mRNA evades NMD through autoregulated nuclear export, engaging a distinct cytoplasmic decay pathway.
Purpose of the Study:
- To elucidate the transcript-specific cytoplasmic decay mechanism of yeast YRA1 pre-mRNA.
- To identify the roles of Edc3p and intronic elements in YRA1 pre-mRNA degradation.
- To understand the interplay between translational repression and NMD evasion in YRA1 pre-mRNA regulation.
Main Methods:
- Investigated Edc3p-mediated degradation of YRA1 pre-mRNA.
- Analyzed the function of five modular elements within the YRA1 intron.
- Examined the role of the Mex67p/Mtr2p export receptor in translational repression and NMD susceptibility.
Main Results:
- YRA1 pre-mRNA degradation by Edc3p is translation-independent.
- Five intronic elements control Edc3p substrate targeting and translational repression.
- Mex67p/Mtr2p mediates translational repression, enhancing Edc3p specificity by inhibiting NMD.
Conclusions:
- YRA1 pre-mRNA degradation is a regulated process involving translational repression and Edc3p-mediated decapping.
- Specific intronic elements dictate substrate recognition and translational control.
- The pathway ensures efficient degradation while preventing premature NMD, highlighting complex RNA regulation.
Related Concept Videos
mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability
mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability
Regulation of the Unfolded Protein Response
Nuclear Export of mRNA
Nuclear Export of mRNA
Regulation of Expression at Multiple Steps
