Ribosome Synthesis in Saccharomyces cerevisiae | …

After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a newround of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5γ′-(β,γ-imido)triphosphate did not function at all. The kcat of eEF3 was 1.12 min-1, which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated under ionic conditions close to those existing in vivo, suggesting that they are ready to enter the initiation process. Based onour experimental techniques used in this paper, the release of mRNA and tRNA and ribosome dissociation took place simultaneously. No 40S•mRNA complex was observed, indicating that eEF3 action promotes ribosome recycling, not reinitiation.

Ribosomal RNA synthesis in Saccharomyces cerevisiae

Functional analysis of saccharomyces cerevisiae ribosomal protein Rpl3p in ribosome synthesis.

Functional analysis of Saccharomyces cerevisiae …

Expression of hepatitis B virus core antigen gene in Saccharomyces cerevisiae: syntehsis of two polypeptides translated from different initiation codons.

Functional analysis of Saccharomyces cerevisiae ..

The Saccharomyces cerevisiae temperature-sensitive (ts) allele nip7-1 exhibits phenotypes associated with defects in the translation apparatus, including hypersensitivity to paromomycin and accumulation of halfmer polysomes. The cloned NIP7+ gene complemented the nip7-1 ts growth defect, the paromomycin hypersensitivity, and the halfmer defect. NIP7 encodes a 181-amino-acid protein (21 kDa) with homology to predicted products of open reading frames from humans, Caenorhabditis elegans, and Arabidopsis thaliana, indicating that Nip7p function is evolutionarily conserved. Gene disruption analysis demonstrated that NIP7 is essential for growth. A fraction of Nip7p cosedimented through sucrose gradients with free 60S ribosomal subunits but not with 80S monosomes or polysomal ribosomes, indicating that it is not a ribosomal protein. Nip7p was found evenly distributed throughout the cytoplasm and nucleus by indirect immunofluorescence; however, in vivo localization of a Nip7p-green fluorescent protein fusion protein revealed that a significant amount of Nip7p is present inside the nucleus, most probably in the nucleolus. Depletion of Nip7-1p resulted in a decrease in protein synthesis rates, accumulation of halfmers, reduced levels of 60S subunits, and, ultimately, cessation of growth. Nip7-1p-depleted cells showed defective pre-rRNA processing, including accumulation of the 35S rRNA precursor, presence of a 23S aberrant precursor, decreased 20S pre-rRNA levels, and accumulation of 27S pre-rRNA. Delayed processing of 27S pre-rRNA appeared to be the cause of reduced synthesis of 25S rRNA relative to 18S rRNA, which may be responsible for the deficit of 60S subunits in these cells.

Ribosome Biogenesis in the Yeast Saccharomyces cerevisiae

1. Cabanas M. et al., 1978. Dual interference of Hygromycin B with ribosomal translocation and with Aminoacyl-tRNA recognition. Eur. J. Biochem. 87:21‑7.
2. Gonzales, A. et al., 1978. Studies on the mode of action of hygromycin B, an inhibitor of translocation in eukaryotes. Biochem Biophys Acta 521:459‑69.
3. Gritz L. & Davies J., 1983. Plasmid-encoded hygromycin B resistance: the sequence of hygromycin B phosphotransferase gene and its expression in Escherichia coli and Saccharomyces cerevisiae. Gene 25:179-88.
4. Cullen D. et al., 1987. Transformation of Aspergillus nidulans with the hygromycin-resistance gene, hph. Gene 57:21-6.
5. Santerre R. et al., 1984. Expression of prokaryotic genes for hygromycin B and G418 resistance as dominant-selection markers in mouse L cells. Gene 30:147-56.

Ribosome synthesis in Saccharomyces cerevisiae

AB - After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a newround of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5γ′-(β,γ-imido)triphosphate did not function at all. The kcat of eEF3 was 1.12 min-1, which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated under ionic conditions close to those existing in vivo, suggesting that they are ready to enter the initiation process. Based onour experimental techniques used in this paper, the release of mRNA and tRNA and ribosome dissociation took place simultaneously. No 40S•mRNA complex was observed, indicating that eEF3 action promotes ribosome recycling, not reinitiation.

and 5.8S rRNAs in wild-type cells of Saccharomyces cerevisiae

N2 - After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a newround of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5γ′-(β,γ-imido)triphosphate did not function at all. The kcat of eEF3 was 1.12 min-1, which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated under ionic conditions close to those existing in vivo, suggesting that they are ready to enter the initiation process. Based onour experimental techniques used in this paper, the release of mRNA and tRNA and ribosome dissociation took place simultaneously. No 40S•mRNA complex was observed, indicating that eEF3 action promotes ribosome recycling, not reinitiation.