Skip to main content
NCBI home page
Molecular and Cellular Biology logoLink to Molecular and Cellular Biology
. 1991 Jan;11(1):486–496. doi: 10.1128/mcb.11.1.486

Suppression of ribosomal reinitiation at upstream open reading frames in amino acid-starved cells forms the basis for GCN4 translational control.

J P Abastado 1, P F Miller 1, B M Jackson 1, A G Hinnebusch 1
PMCID: PMC359655  PMID: 1986242

Abstract

GCN4 encodes a transcriptional activator of amino acid-biosynthetic genes in Saccharomyces cerevisiae that is regulated at the translational level by upstream open reading frames (uORFs) in its mRNA leader. uORF4 (counting from the 5' end) is sufficient to repress GCN4 under nonstarvation conditions; uORF1 is required to overcome the inhibitory effect of uORF4 and stimulate GCN4 translation in amino acid-starved cells. Insertions of sequences with the potential to form secondary structure around uORF4 abolish derepression, indicating that ribosomes reach GCN4 by traversing uORF4 sequences rather than by binding internally to the GCN4 start site. By showing that wild-type regulation occurred even when uORF4 was elongated to overlap GCN4 by 130 nucleotides, we provide strong evidence that those ribosomes which translate GCN4 do so by ignoring the uORF4 AUG start codon. This conclusion is in accord with the fact that translation of a uORF4-lacZ fusion was lower in a derepressed gcd1 mutant than in a nonderepressible gcn2 strain. We also show that increasing the distance between uORF1 and uORF4 to the wild-type spacing that separates uORF1 from GCN4 specifically impaired the ability of uORF1 to derepress GCN4 translation. As expected, this alteration led to increased uORF4-lacZ translation in gcd1 cells. Our results suggest that under starvation conditions, a substantial fraction of ribosomes that translate uORF1 fail to reassemble the factors needed for reinitiation by the time they scan to uORF4, but become competent to reinitiate after scanning the additional sequences to GCN4. Under nonstarvation conditions, ribosomes would recover more rapidly from uORF1 translation, causing them all to reinitiate at uORF4 rather than at GCN4.

Full text

PDF
486

Images in this article

490Image
on p.490
490Image
on p.490
491Image
on p.491

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Baim S. B., Pietras D. F., Eustice D. C., Sherman F. A mutation allowing an mRNA secondary structure diminishes translation of Saccharomyces cerevisiae iso-1-cytochrome c. Mol Cell Biol. 1985 Aug;5(8):1839–1846. doi: 10.1128/mcb.5.8.1839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Baim S. B., Sherman F. mRNA structures influencing translation in the yeast Saccharomyces cerevisiae. Mol Cell Biol. 1988 Apr;8(4):1591–1601. doi: 10.1128/mcb.8.4.1591. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Cigan A. M., Donahue T. F. Sequence and structural features associated with translational initiator regions in yeast--a review. Gene. 1987;59(1):1–18. doi: 10.1016/0378-1119(87)90261-7. [DOI] [PubMed] [Google Scholar]
  4. Cigan A. M., Feng L., Donahue T. F. tRNAi(met) functions in directing the scanning ribosome to the start site of translation. Science. 1988 Oct 7;242(4875):93–97. doi: 10.1126/science.3051379. [DOI] [PubMed] [Google Scholar]
  5. Cigan A. M., Pabich E. K., Donahue T. F. Mutational analysis of the HIS4 translational initiator region in Saccharomyces cerevisiae. Mol Cell Biol. 1988 Jul;8(7):2964–2975. doi: 10.1128/mcb.8.7.2964. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Donahue T. F., Cigan A. M. Genetic selection for mutations that reduce or abolish ribosomal recognition of the HIS4 translational initiator region. Mol Cell Biol. 1988 Jul;8(7):2955–2963. doi: 10.1128/mcb.8.7.2955. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Groebe D. R., Uhlenbeck O. C. Characterization of RNA hairpin loop stability. Nucleic Acids Res. 1988 Dec 23;16(24):11725–11735. doi: 10.1093/nar/16.24.11725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Hinnebusch A. G. A hierarchy of trans-acting factors modulates translation of an activator of amino acid biosynthetic genes in Saccharomyces cerevisiae. Mol Cell Biol. 1985 Sep;5(9):2349–2360. doi: 10.1128/mcb.5.9.2349. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hinnebusch A. G. Evidence for translational regulation of the activator of general amino acid control in yeast. Proc Natl Acad Sci U S A. 1984 Oct;81(20):6442–6446. doi: 10.1073/pnas.81.20.6442. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hinnebusch A. G., Fink G. R. Positive regulation in the general amino acid control of Saccharomyces cerevisiae. Proc Natl Acad Sci U S A. 1983 Sep;80(17):5374–5378. doi: 10.1073/pnas.80.17.5374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hinnebusch A. G., Jackson B. M., Mueller P. P. Evidence for regulation of reinitiation in translational control of GCN4 mRNA. Proc Natl Acad Sci U S A. 1988 Oct;85(19):7279–7283. doi: 10.1073/pnas.85.19.7279. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hinnebusch A. G. Mechanisms of gene regulation in the general control of amino acid biosynthesis in Saccharomyces cerevisiae. Microbiol Rev. 1988 Jun;52(2):248–273. doi: 10.1128/mr.52.2.248-273.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Ito H., Fukuda Y., Murata K., Kimura A. Transformation of intact yeast cells treated with alkali cations. J Bacteriol. 1983 Jan;153(1):163–168. doi: 10.1128/jb.153.1.163-168.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Johansen H., Schümperli D., Rosenberg M. Affecting gene expression by altering the length and sequence of the 5' leader. Proc Natl Acad Sci U S A. 1984 Dec;81(24):7698–7702. doi: 10.1073/pnas.81.24.7698. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Klionsky D. J., Banta L. M., Emr S. D. Intracellular sorting and processing of a yeast vacuolar hydrolase: proteinase A propeptide contains vacuolar targeting information. Mol Cell Biol. 1988 May;8(5):2105–2116. doi: 10.1128/mcb.8.5.2105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kozak M. Context effects and inefficient initiation at non-AUG codons in eucaryotic cell-free translation systems. Mol Cell Biol. 1989 Nov;9(11):5073–5080. doi: 10.1128/mcb.9.11.5073. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kozak M. Effects of intercistronic length on the efficiency of reinitiation by eucaryotic ribosomes. Mol Cell Biol. 1987 Oct;7(10):3438–3445. doi: 10.1128/mcb.7.10.3438. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Kozak M. The scanning model for translation: an update. J Cell Biol. 1989 Feb;108(2):229–241. doi: 10.1083/jcb.108.2.229. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  20. Lucchini G., Hinnebusch A. G., Chen C., Fink G. R. Positive regulatory interactions of the HIS4 gene of Saccharomyces cerevisiae. Mol Cell Biol. 1984 Jul;4(7):1326–1333. doi: 10.1128/mcb.4.7.1326. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Miller P. F., Hinnebusch A. G. Sequences that surround the stop codons of upstream open reading frames in GCN4 mRNA determine their distinct functions in translational control. Genes Dev. 1989 Aug;3(8):1217–1225. doi: 10.1101/gad.3.8.1217. [DOI] [PubMed] [Google Scholar]
  22. Mueller P. P., Harashima S., Hinnebusch A. G. A segment of GCN4 mRNA containing the upstream AUG codons confers translational control upon a heterologous yeast transcript. Proc Natl Acad Sci U S A. 1987 May;84(9):2863–2867. doi: 10.1073/pnas.84.9.2863. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Mueller P. P., Hinnebusch A. G. Multiple upstream AUG codons mediate translational control of GCN4. Cell. 1986 Apr 25;45(2):201–207. doi: 10.1016/0092-8674(86)90384-3. [DOI] [PubMed] [Google Scholar]
  24. Mueller P. P., Jackson B. M., Miller P. F., Hinnebusch A. G. The first and fourth upstream open reading frames in GCN4 mRNA have similar initiation efficiencies but respond differently in translational control to change in length and sequence. Mol Cell Biol. 1988 Dec;8(12):5439–5447. doi: 10.1128/mcb.8.12.5439. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Peabody D. S., Berg P. Termination-reinitiation occurs in the translation of mammalian cell mRNAs. Mol Cell Biol. 1986 Jul;6(7):2695–2703. doi: 10.1128/mcb.6.7.2695. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Pelletier J., Sonenberg N. Internal initiation of translation of eukaryotic mRNA directed by a sequence derived from poliovirus RNA. Nature. 1988 Jul 28;334(6180):320–325. doi: 10.1038/334320a0. [DOI] [PubMed] [Google Scholar]
  27. Saiki R. K., Scharf S., Faloona F., Mullis K. B., Horn G. T., Erlich H. A., Arnheim N. Enzymatic amplification of beta-globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. Science. 1985 Dec 20;230(4732):1350–1354. doi: 10.1126/science.2999980. [DOI] [PubMed] [Google Scholar]
  28. Sedman S. A., Good P. J., Mertz J. E. Leader-encoded open reading frames modulate both the absolute and relative rates of synthesis of the virion proteins of simian virus 40. J Virol. 1989 Sep;63(9):3884–3893. doi: 10.1128/jvi.63.9.3884-3893.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Sonenberg N. Cap-binding proteins of eukaryotic messenger RNA: functions in initiation and control of translation. Prog Nucleic Acid Res Mol Biol. 1988;35:173–207. doi: 10.1016/s0079-6603(08)60614-5. [DOI] [PubMed] [Google Scholar]
  30. Thireos G., Penn M. D., Greer H. 5' untranslated sequences are required for the translational control of a yeast regulatory gene. Proc Natl Acad Sci U S A. 1984 Aug;81(16):5096–5100. doi: 10.1073/pnas.81.16.5096. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Thomas K. R., Capecchi M. R. Introduction of homologous DNA sequences into mammalian cells induces mutations in the cognate gene. Nature. 1986 Nov 6;324(6092):34–38. doi: 10.1038/324034a0. [DOI] [PubMed] [Google Scholar]
  32. Tzamarias D., Alexandraki D., Thireos G. Multiple cis-acting elements modulate the translational efficiency of GCN4 mRNA in yeast. Proc Natl Acad Sci U S A. 1986 Jul;83(13):4849–4853. doi: 10.1073/pnas.83.13.4849. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Tzamarias D., Roussou I., Thireos G. Coupling of GCN4 mRNA translational activation with decreased rates of polypeptide chain initiation. Cell. 1989 Jun 16;57(6):947–954. doi: 10.1016/0092-8674(89)90333-4. [DOI] [PubMed] [Google Scholar]
  34. Tzamarias D., Thireos G. Evidence that the GCN2 protein kinase regulates reinitiation by yeast ribosomes. EMBO J. 1988 Nov;7(11):3547–3551. doi: 10.1002/j.1460-2075.1988.tb03231.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Williams N. P., Hinnebusch A. G., Donahue T. F. Mutations in the structural genes for eukaryotic initiation factors 2 alpha and 2 beta of Saccharomyces cerevisiae disrupt translational control of GCN4 mRNA. Proc Natl Acad Sci U S A. 1989 Oct;86(19):7515–7519. doi: 10.1073/pnas.86.19.7515. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Williams N. P., Mueller P. P., Hinnebusch A. G. The positive regulatory function of the 5'-proximal open reading frames in GCN4 mRNA can be mimicked by heterologous, short coding sequences. Mol Cell Biol. 1988 Sep;8(9):3827–3836. doi: 10.1128/mcb.8.9.3827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Wolfner M., Yep D., Messenguy F., Fink G. R. Integration of amino acid biosynthesis into the cell cycle of Saccharomyces cerevisiae. J Mol Biol. 1975 Aug 5;96(2):273–290. doi: 10.1016/0022-2836(75)90348-4. [DOI] [PubMed] [Google Scholar]
  38. Zoller M. J., Smith M. Oligonucleotide-directed mutagenesis using M13-derived vectors: an efficient and general procedure for the production of point mutations in any fragment of DNA. Nucleic Acids Res. 1982 Oct 25;10(20):6487–6500. doi: 10.1093/nar/10.20.6487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Zuker M., Stiegler P. Optimal computer folding of large RNA sequences using thermodynamics and auxiliary information. Nucleic Acids Res. 1981 Jan 10;9(1):133–148. doi: 10.1093/nar/9.1.133. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Molecular and Cellular Biology are provided here courtesy of Taylor & Francis

RESOURCES

OSZAR »