Nonsense-mediated mRNA decay in yeast does not require PAB1 or a poly(A) tail.
Eukaryotic mRNAs harboring premature translation termination codons are recognized and rapidly degraded by the nonsense-mediated mRNA decay (NMD) pathway. The mechanism for discriminating between mRNAs that terminate translation prematurely and those subject to termination at natural stop codons remains unclear. Studies in multiple organisms indicate that proximity of the termination codon to the 3' poly(A) tail and the poly(A) RNA-binding protein, PAB1, constitute the critical determinant in NMD substrate recognition. We demonstrate that mRNA in yeast lacking a poly(A) tail can be destabilized by introduction of a premature termination codon and, importantly, that this mRNA is a substrate of the NMD machinery. We further show that, in cells lacking Pab1p, mRNA substrate recognition and destabilization by NMD are intact. These results establish that neither the poly(A) tail nor PAB1 is required in yeast for discrimination of nonsense-codon-containing mRNA from normal by NMD.
Meaux
Stacie
S
Department of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston, Houston, TX 77030, USA.
van Hoof
Ambro
A
Baker
Kristian E
KE
D018389:Codon, Nonsense; D005686:Galactokinase / Q000235:genetics; D017930:Genes, Reporter; D005813:Genes, Synthetic; D049452:Green Fluorescent Proteins / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D039102:Poly(A)-Binding Proteins / Q000502:physiology*; D020871:RNA Stability / Q000502:physiology*; D016337:RNA, Catalytic / Q000235:genetics; D012333:RNA, Messenger / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
D018389:Codon, Nonsense; D039102:Poly(A)-Binding Proteins; D016337:RNA, Catalytic; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C427204:hammerhead ribozyme; C450100:pab1 protein, S cerevisiae; D049452:Green Fluorescent Proteins; C524219:GAL1 protein, S cerevisiae; D005686:Galactokinase