Functional mapping of the translation-dependent instability element of yeast MATalpha1 mRNA
UMass Chan Affiliations
Department of Molecular Genetics and MicrobiologyDocument Type
Journal ArticlePublication Date
1996-07-01Keywords
AllelesBase Sequence
Codon
Fungal Proteins
Genes, Fungal
Molecular Sequence Data
Mutagenesis, Site-Directed
Oligodeoxyribonucleotides
*Peptide Biosynthesis
Peptide Chain Termination, Translational
Peptides
Pheromones
Plasmids
*Protein Biosynthesis
*RNA Helicases
RNA, Messenger
Recombinant Proteins
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
Transcription, Genetic
Biochemistry, Biophysics, and Structural Biology
Cell and Developmental Biology
Cell Biology
Molecular Biology
Metadata
Show full item recordAbstract
The determinants of mRNA stability include specific cis-acting destabilizing sequences located within mRNA coding and noncoding regions. We have developed an approach for mapping coding-region instability sequences in unstable yeast mRNAs that exploits the link between mRNA translation and turnover and the dependence of nonsense-mediated mRNA decay on the activity of the UPF1 gene product. This approach, which involves the systematic insertion of in-frame translational termination codons into the coding sequence of a gene of interest in a upf1delta strain, differs significantly from conventional methods for mapping cis-acting elements in that it causes minimal perturbations to overall mRNA structure. Using the previously characterized MATalpha1 mRNA as a model, we have accurately localized its 65-nucleotide instability element (IE) within the protein coding region. Termination of translation 5' to this element stabilized the MATalpha1 mRNA two- to threefold relative to wild-type transcripts. Translation through the element was sufficient to restore an unstable decay phenotype, while internal termination resulted in different extents of mRNA stabilization dependent on the precise location of ribosome stalling. Detailed mutagenesis of the element's rare-codon/AU-rich sequence boundary revealed that the destabilizing activity of the MATalpha1 IE is observed when the terminal codon of the element's rare-codon interval is translated. This region of stability transition corresponds precisely to a MATalpha1 IE sequence previously shown to be complementary to 18S rRNA. Deletion of three nucleotides 3' to this sequence shifted the stability boundary one codon 5' to its wild-type location. Conversely, constructs containing an additional three nucleotides at this same location shifted the transition downstream by an equivalent sequence distance. Our results suggest a model in which the triggering of MATalpha1 mRNA destabilization results from establishment of an interaction between translating ribosomes and a downstream sequence element. Furthermore, our data provide direct molecular evidence for a relationship between mRNA turnover and mRNA translation.Source
Mol Cell Biol. 1996 Jul;16(7):3833-43. Link to article on publisher's websitePermanent Link to this Item
http://hdl.handle.net/20.500.14038/38590PubMed ID
8668201Related Resources
Link to Article in PubMedRights
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