An aminoacylation-dependent nuclear tRNA export pathway in yeast.
Yeast Los1p, the homolog of human exportin-t, mediates nuclear export of tRNA. Using fluorescence in situ hybridization, we could show that the export of some intronless tRNA species is not detectably affected by the disruption of LOS1. To find other factors that facilitate tRNA export, we performed a suppressor screen of a synthetically lethal los1 mutant and identified the essential translation elongation factor eEF-1A. Mutations in eEF-1A impaired nuclear export of all tRNAs tested, which included both spliced and intronless species. An even stronger defect in nuclear exit of tRNA was observed under conditions that inhibited tRNA aminoacylation. In all cases, inhibition of tRNA export led to nucleolar accumulation of mature tRNAs. Our data show that tRNA aminoacylation and eEF-1A are required for efficient nuclear tRNA export in yeast and suggest coordination between the protein translation and the nuclear tRNA processing and transport machineries.
Grosshans
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H
Biochemie-Zentrum Heidelberg (BZH), University of Heidelberg, D-69120 Heidelberg, Germany.
Hurt
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Simos
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D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015698:Genomic Library; D006801:Humans; D007438:Introns; D016296:Mutagenesis; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D009690:Nucleic Acid Conformation; D029543:Nucleocytoplasmic Transport Proteins; D015345:Oligonucleotide Probes; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000235:genetics*; D012355:RNA, Transfer, Ile / Q000737:chemistry / Q000235:genetics; D012356:RNA, Transfer, Leu / Q000737:chemistry / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins
D002352:Carrier Proteins; D005656:Fungal Proteins; C408090:Los1 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D015345:Oligonucleotide Probes; D012346:RNA, Transfer, Amino Acyl; D012355:RNA, Transfer, Ile; D012356:RNA, Transfer, Leu; D029701:Saccharomyces cerevisiae Proteins; C503618:XPOT protein, human; D012343:RNA, Transfer