title: Overexpression of truncated Nmd3p inhibits protein synthesis in yeast.
abstract: The yeast NMD3 gene was identified in a two-hybrid screen using the nonsense-mediated mRNA decay factor, Upf1p, as bait. NMD3 was shown to encode an essential, highly conserved protein that associated principally with free 60S ribosomal subunits. Overexpression of a truncated form of Nmd3p, lacking 100 C-terminal amino acids and most of its Upf1p-interacting domain, had dominant-negative effects on both cell growth and protein synthesis and promoted the formation of polyribosome half-mers. These effects were eliminated by truncation of an additional 100 amino acids from Nmd3p. Overexpression of the nmd3delta100 allele also led to increased synthesis and destabilization of some ribosomal protein mRNAs, and increased synthesis and altered processing of 35S pre-rRNA. Our data suggest that Nmd3p has a role in the formation, function, or maintenance of the 60S ribosomal subunit and may provide a link for Upf1p to 80S monosomes.
authors.affiliation: Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655-0122, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Belk
authors.forename: F
authors.initials: F
authors.lastname: He
authors.forename: A
authors.initials: A
authors.lastname: Jacobson
mesh_terms: D000595:Amino Acid Sequence; D015152:Blotting, Northern; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005690:Galactose / Q000494:pharmacology; D015966:Gene Expression Regulation, Fungal; D005799:Genes, Dominant; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
chemical_list: D005656:Fungal Proteins; C117894:NMD3 protein, S cerevisiae; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C074151:NAM7 protein, S cerevisiae; D020365:RNA Helicases; D005690:Galactose