Translation and a 42-nucleotide segment within the coding region of the mRNA encoded by the MAT alpha 1 gene are involved in promoting rapid mRNA decay in yeast.
In yeast, the mRNA encoded by the MAT alpha 1 gene is unstable (t1/2 = 5 min) and the mRNAs encoded by the ACT1 gene (t1/2 = 30 min) and the PGK1 gene (t1/2 = 45 min) are stable. To understand the RNA structural features that dictate mRNA decay rates in yeast, we have constructed PGK1/MAT alpha 1 and ACT1/MAT alpha 1 gene fusions and analyzed the decay rates of the resultant chimeric transcripts. Fusion of a MAT alpha 1 segment containing 73% of the coding region and the 3' untranslated region to either of the stable genes is sufficient to cause rapid decay of the chimeric mRNAs (t1/2 = 6-7.5 min). Sequences required for this rapid decay are not found in the MAT alpha 1 3' untranslated region but are located within a 42-nucleotide segment of the coding region that has a high content (8 out of 14) of rare codons. Introduction of a translational stop codon upstream of this region stabilizes the hybrid mRNAs, indicating that the rapid decay promoted by these sequences is dependent on ribosomal translocation.
Parker
R
R
Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655.
Jacobson
A
A
D001483:Base Sequence; D002678:Chimera; D005800:Genes, Fungal; D007700:Kinetics; D008969:Molecular Sequence Data; D010957:Plasmids; D014176:Protein Biosynthesis; D012331:RNA, Fungal / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic
D012331:RNA, Fungal; D012333:RNA, Messenger