Translational control by internal ribosome entry site in Saccharomyces cerevisiae.

To confirm the active involvement of the internal ribosome entry site (IRES)-dependent translation in living eukaryotes, Saccharomyces cerevisiae and HAP4 IRES were used for in vitro and in vivo experiments. Since HAP4 protein might be required for activating mRNAs transcription in yeast cells when they are released from catabolite repression, the translational efficiency of HAP4 mRNA is presumed to increase under such a condition. The in vitro experiment showed clearly that the translational mechanism was shifted from the cap-dependent to the completely IRES-dependent translation when the yeast cells were derepressed from catabolite repression. From in vivo experiment, it was confirmed that the IRES-dependent translational efficiency was in a low level at the beginning of the stationary growth phase, and was enhanced at the glucose-exhausted phase. These results indicate that yeast cells on the catabolite derepressed condition could get a large amount of HAP4 protein for the completely IRES-dependent translation, while the IRES-dependent translational efficiency is increased. It has been proven that IRES functions directing the initiation of translation in living yeast cells.

[1]  A. Nomoto,et al.  Internal ribosome entry site within hepatitis C virus RNA , 1992, Journal of virology.

[2]  P. Brown,et al.  Exploring the metabolic and genetic control of gene expression on a genomic scale. , 1997, Science.

[3]  B. Semler,et al.  Translation Initiation of a Cardiac Voltage-gated Potassium Channel by Internal Ribosome Entry* , 1998, The Journal of Biological Chemistry.

[4]  M. Hentze,et al.  Starting at the Beginning, Middle, and End: Translation Initiation in Eukaryotes , 1997, Cell.

[5]  E. Kobatake,et al.  Novel cap-independent translation with the 5′-noncoding region of L-A virus mRNA , 2004, Biotechnology Letters.

[6]  C. Berset,et al.  The TOR (target of rapamycin) signal transduction pathway regulates the stability of translation initiation factor eIF4G in the yeast Saccharomyces cerevisiae. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[7]  V. M. Pain,et al.  The C‐terminal domain of eukaryotic protein synthesis initiation factor (eIF) 4G is sufficient to support cap‐independent translation in the absence of eIF4E. , 1996, The EMBO journal.

[8]  M. Wickens,et al.  Translational controls impinging on the 5'-untranslated region and initiation factor proteins. , 1997, Current opinion in genetics & development.

[9]  G. Dubyak,et al.  Detection of local ATP release from activated platelets using cell surface-attached firefly luciferase. , 1999, American journal of physiology. Cell physiology.

[10]  H. Ronne.  Glucose repression in fungi. , 1995, Trends in genetics : TIG.

[11]  J. Gancedo.  Yeast Carbon Catabolite Repression , 1998, Microbiology and Molecular Biology Reviews.

[12]  R. Rhoads,et al.  Internal Initiation of Translation Directed by the 5′-Untranslated Region of the mRNA for eIF4G, a Factor Involved in the Picornavirus-induced Switch from Cap-dependent to Internal Initiation (*) , 1996, The Journal of Biological Chemistry.

[13]  A. Hinnebusch,et al.  Translational Regulation of Yeast GCN4 , 1997, The Journal of Biological Chemistry.

[14]  C. Grant,et al.  Stationary‐phase regulation of the Saccharomyces cerevisiaeSOD2 gene is dependent on additive effects of HAP2/3/4/5‐ and STRE‐binding elements , 1997, Molecular microbiology.

[15]  M. Werner-Washburne,et al.  Protein synthesis in long-term stationary-phase cultures of Saccharomyces cerevisiae , 1994, Journal of bacteriology.

[16]  P. Brown,et al.  Identification of eukaryotic mRNAs that are translated at reduced cap binding complex eIF4F concentrations using a cDNA microarray. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[17]  A. Prats,et al.  Alternative Translation of the Proto-oncogene c-mycby an Internal Ribosome Entry Site* , 1997, The Journal of Biological Chemistry.

[18]  W. Merrick,et al.  Biochemical and Kinetic Characterization of the RNA Helicase Activity of Eukaryotic Initiation Factor 4A* , 1999, The Journal of Biological Chemistry.

[19]  Yi Liu,et al.  Thermally Regulated Translational Control of FRQ Mediates Aspects of Temperature Responses in the Neurospora Circadian Clock , 1997, Cell.

[20]  P Sarnow,et al.  Cap-dependent and cap-independent translation by internal initiation of mRNAs in cell extracts prepared from Saccharomyces cerevisiae , 1994, Molecular and cellular biology.

[21]  G M Edelman,et al.  Transcript leader regions of two Saccharomyces cerevisiae mRNAs contain internal ribosome entry sites that function in living cells. , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[22]  J. Gancedo.  Carbon catabolite repression in yeast. , 1992, European journal of biochemistry.

[23]  A. Prats,et al.  Translation of CUG- but not AUG-initiated forms of human fibroblast growth factor 2 is activated in transformed and stressed cells , 1996, The Journal of cell biology.

[24]  M. Kozak.  Initiation of translation in prokaryotes and eukaryotes. , 1999, Gene.

[25]  M. Choder,et al.  Starved Saccharomyces cerevisiae Cells Have the Capacity to Support Internal Initiation of Translation* , 1999, The Journal of Biological Chemistry.

[26]  R. Panniers,et al.  Heat shock impairs the interaction of cap-binding protein complex with 5' mRNA cap. , 1991, The Journal of biological chemistry.

[27]  L. Guarente,et al.  Identification and characterization of HAP4: a third component of the CCAAT-bound HAP2/HAP3 heteromer. , 1989, Genes & development.

[28]  P. Einat,et al.  Translation of Vascular Endothelial Growth Factor mRNA by Internal Ribosome Entry: Implications for Translation under Hypoxia , 1998, Molecular and Cellular Biology.

[29]  J. Gallant,et al.  Ribosomes can slide over and beyond "hungry" codons, resuming protein chain elongation many nucleotides downstream. , 1998, Proceedings of the National Academy of Sciences of the United States of America.