title: Nonsense-mediated mRNA decay mutation in Aspergillus nidulans.
abstract: An Aspergillus nidulans mutation, designated nmdA1, has been selected as a partial suppressor of a frameshift mutation and shown to truncate the homologue of the Saccharomyces cerevisiae nonsense-mediated mRNA decay (NMD) surveillance component Nmd2p/Upf2p. nmdA1 elevates steady-state levels of premature termination codon-containing transcripts, as demonstrated using mutations in genes encoding xanthine dehydrogenase (hxA), urate oxidase (uaZ), the transcription factor mediating regulation of gene expression by ambient pH (pacC), and a protease involved in pH signal transduction (palB). nmdA1 can also stabilize pre-mRNA (unspliced) and wild-type transcripts of certain genes. Certain premature termination codon-containing transcripts which escape NMD are relatively stable, a feature more in common with certain nonsense codon-containing mammalian transcripts than with those in S. cerevisiae. As in S. cerevisiae, 5' nonsense codons are more effective at triggering NMD than 3' nonsense codons. Unlike the mammalian situation but in common with S. cerevisiae and other lower eukaryotes, A. nidulans is apparently impervious to the position of premature termination codons with respect to the 3' exon-exon junction.
authors.affiliation: Department of Molecular Microbiology and Infection, Flowers Building, Imperial College London, Armstrong Road, London SW7 2AZ, United Kingdom.
authors.forename: Igor Y
authors.initials: IY
authors.lastname: Morozov
authors.forename: Susana
authors.initials: S
authors.lastname: Negrete-Urtasun
authors.forename: Joan
authors.initials: J
authors.lastname: Tilburn
authors.forename: Christine A
authors.initials: CA
authors.lastname: Jansen
authors.forename: Mark X
authors.initials: MX
authors.lastname: Caddick
authors.forename: Herbert N
authors.initials: HN
authors.lastname: Arst
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism; D018389:Codon, Nonsense; D005091:Exons; D016368:Frameshift Mutation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D020871:RNA Stability; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014503:Urate Oxidase / Q000235:genetics / Q000378:metabolism; D014969:Xanthine Oxidase / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C079728:AreA protein, Aspergillus nidulans; D018389:Codon, Nonsense; D005656:Fungal Proteins; C092470:NMD2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D018698:Glutamic Acid; D014969:Xanthine Oxidase; D014503:Urate Oxidase; D009584:Nitrogen