Abstract
The 40-S subunit of eukaryotic ribosomes binds to the capped 5'-end of mRNA and scans for the first AUG in a favorable sequence context to initiate translation. Most eukaryotic mRNAs therefore have a short 5'- untranslated region (5'-UTR) and no AUGs upstream of the translational start site; features that seem to assure efficient translation. However, approximately 5-10% of all eukaryotic mRNAs, particularly those encoding for regulatory proteins, have complex leader sequences that seem to compromise translational initiation. The retinoic-acid- receptor-beta 2 (RAR beta 2) mRNA is such a transcript with a long (461 nucleotides) 5'-UTR that contains five, partially overlapping, upstream open reading frames (uORFs) that precede the major ORF. We have begun to investigate the function of this complex 5'-UTR in transgenic mice, by introducing mutations in the start/stop codons of the uORFs in RAR beta 2-lacZ reporter constructs. When we compared the expression patterns of mutant and wild-type constructs we found that these mutations affected expression of the downstream RAR beta 2-ORF, resulting in an altered regulation of RAR beta 2-lacZ expression in heart and brain. Other tissues were unaffected. RNA analysis of adult tissues demonstrated that the uORFs act at the level of translation; adult brains and hearts of transgenic mice carrying a construct with either the wild-type or a mutant UTR, had the same levels of mRNA, but only the mutant produced protein. Our study outlines an unexpected role for uORFs: control of tissue-specific and developmentally regulated gene expression.
Full Text
The Full Text of this article is available as a PDF (5.2 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Abastado J. P., Miller P. F., Hinnebusch A. G. A quantitative model for translational control of the GCN4 gene of Saccharomyces cerevisiae. New Biol. 1991 May;3(5):511–524. [PubMed] [Google Scholar]
- Arrick B. A., Lee A. L., Grendell R. L., Derynck R. Inhibition of translation of transforming growth factor-beta 3 mRNA by its 5' untranslated region. Mol Cell Biol. 1991 Sep;11(9):4306–4313. doi: 10.1128/mcb.11.9.4306-4313.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chen J. J., Throop M. S., Gehrke L., Kuo I., Pal J. K., Brodsky M., London I. M. Cloning of the cDNA of the heme-regulated eukaryotic initiation factor 2 alpha (eIF-2 alpha) kinase of rabbit reticulocytes: homology to yeast GCN2 protein kinase and human double-stranded-RNA-dependent eIF-2 alpha kinase. Proc Natl Acad Sci U S A. 1991 Sep 1;88(17):7729–7733. doi: 10.1073/pnas.88.17.7729. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cooper J. A., Farrell P. J. Extracts of interferon-treated cells can inhibit reticulocyte lysate protein synthesis. Biochem Biophys Res Commun. 1977 Jul 11;77(1):124–131. doi: 10.1016/s0006-291x(77)80173-3. [DOI] [PubMed] [Google Scholar]
- Darveau A., Pelletier J., Sonenberg N. Differential efficiencies of in vitro translation of mouse c-myc transcripts differing in the 5' untranslated region. Proc Natl Acad Sci U S A. 1985 Apr;82(8):2315–2319. doi: 10.1073/pnas.82.8.2315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- De Benedetti A., Baglioni C. Inhibition of mRNA binding to ribosomes by localized activation of dsRNA-dependent protein kinase. Nature. 1984 Sep 6;311(5981):79–81. doi: 10.1038/311079a0. [DOI] [PubMed] [Google Scholar]
- Dever T. E., Feng L., Wek R. C., Cigan A. M., Donahue T. F., Hinnebusch A. G. Phosphorylation of initiation factor 2 alpha by protein kinase GCN2 mediates gene-specific translational control of GCN4 in yeast. Cell. 1992 Feb 7;68(3):585–596. doi: 10.1016/0092-8674(92)90193-g. [DOI] [PubMed] [Google Scholar]
- Eichele G. Retinoids in embryonic development. Ann N Y Acad Sci. 1993 Mar 15;678:22–36. doi: 10.1111/j.1749-6632.1993.tb26107.x. [DOI] [PubMed] [Google Scholar]
- Eisel U., Reynolds K., Riddick M., Zimmer A., Niemann H., Zimmer A. Tetanus toxin light chain expression in Sertoli cells of transgenic mice causes alterations of the actin cytoskeleton and disrupts spermatogenesis. EMBO J. 1993 Sep;12(9):3365–3372. doi: 10.1002/j.1460-2075.1993.tb06010.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans R. M. The steroid and thyroid hormone receptor superfamily. Science. 1988 May 13;240(4854):889–895. doi: 10.1126/science.3283939. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Farrell P. J., Balkow K., Hunt T., Jackson R. J., Trachsel H. Phosphorylation of initiation factor elF-2 and the control of reticulocyte protein synthesis. Cell. 1977 May;11(1):187–200. doi: 10.1016/0092-8674(77)90330-0. [DOI] [PubMed] [Google Scholar]
- Hershey J. W. Translational control in mammalian cells. Annu Rev Biochem. 1991;60:717–755. doi: 10.1146/annurev.bi.60.070191.003441. [DOI] [PubMed] [Google Scholar]
- Jackson R. J. Cytoplasmic regulation of mRNA function: the importance of the 3' untranslated region. Cell. 1993 Jul 16;74(1):9–14. doi: 10.1016/0092-8674(93)90290-7. [DOI] [PubMed] [Google Scholar]
- Jaramillo M., Pelletier J., Edery I., Nielsen P. J., Sonenberg N. Multiple mRNAs encode the murine translation initiation factor eIF-4E. J Biol Chem. 1991 Jun 5;266(16):10446–10451. [PubMed] [Google Scholar]
- Kessel M., Gruss P. Open reading frames and translational control. Nature. 1988 Mar 10;332(6160):117–118. doi: 10.1038/332117c0. [DOI] [PubMed] [Google Scholar]
- Koromilas A. E., Lazaris-Karatzas A., Sonenberg N. mRNAs containing extensive secondary structure in their 5' non-coding region translate efficiently in cells overexpressing initiation factor eIF-4E. EMBO J. 1992 Nov;11(11):4153–4158. doi: 10.1002/j.1460-2075.1992.tb05508.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koromilas A. E., Roy S., Barber G. N., Katze M. G., Sonenberg N. Malignant transformation by a mutant of the IFN-inducible dsRNA-dependent protein kinase. Science. 1992 Sep 18;257(5077):1685–1689. doi: 10.1126/science.1382315. [DOI] [PubMed] [Google Scholar]
- Kozak M. An analysis of vertebrate mRNA sequences: intimations of translational control. J Cell Biol. 1991 Nov;115(4):887–903. doi: 10.1083/jcb.115.4.887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Lazaris-Karatzas A., Montine K. S., Sonenberg N. Malignant transformation by a eukaryotic initiation factor subunit that binds to mRNA 5' cap. Nature. 1990 Jun 7;345(6275):544–547. doi: 10.1038/345544a0. [DOI] [PubMed] [Google Scholar]
- Marth J. D., Overell R. W., Meier K. E., Krebs E. G., Perlmutter R. M. Translational activation of the lck proto-oncogene. Nature. 1988 Mar 10;332(6160):171–173. doi: 10.1038/332171a0. [DOI] [PubMed] [Google Scholar]
- Mendelsohn C., Ruberte E., LeMeur M., Morriss-Kay G., Chambon P. Developmental analysis of the retinoic acid-inducible RAR-beta 2 promoter in transgenic animals. Development. 1991 Nov;113(3):723–734. doi: 10.1242/dev.113.3.723. [DOI] [PubMed] [Google Scholar]
- Merrick W. C. Mechanism and regulation of eukaryotic protein synthesis. Microbiol Rev. 1992 Jun;56(2):291–315. doi: 10.1128/mr.56.2.291-315.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- 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]
- Nagpal S., Zelent A., Chambon P. RAR-beta 4, a retinoic acid receptor isoform is generated from RAR-beta 2 by alternative splicing and usage of a CUG initiator codon. Proc Natl Acad Sci U S A. 1992 Apr 1;89(7):2718–2722. doi: 10.1073/pnas.89.7.2718. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nielsen P. J., Trachsel H. The mouse protein synthesis initiation factor 4A gene family includes two related functional genes which are differentially expressed. EMBO J. 1988 Jul;7(7):2097–2105. doi: 10.1002/j.1460-2075.1988.tb03049.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rao C. D., Pech M., Robbins K. C., Aaronson S. A. The 5' untranslated sequence of the c-sis/platelet-derived growth factor 2 transcript is a potent translational inhibitor. Mol Cell Biol. 1988 Jan;8(1):284–292. doi: 10.1128/mcb.8.1.284-292.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reynolds K., Mezey E., Zimmer A. Activity of the beta-retinoic acid receptor promoter in transgenic mice. Mech Dev. 1991 Dec;36(1-2):15–29. doi: 10.1016/0925-4773(91)90068-h. [DOI] [PubMed] [Google Scholar]
- Samuel C. E. Role of the RNA-dependent protein kinase in the regulated expression of genes in transfected cells. Pharmacol Ther. 1992;54(3):307–317. doi: 10.1016/0163-7258(92)90005-k. [DOI] [PubMed] [Google Scholar]
- Shen S., van den Brink C. E., Kruijer W., van der Saag P. T. Embryonic stem cells stably transfected with mRAR beta 2-lacZ exhibit specific expression in chimeric embryos. Int J Dev Biol. 1992 Dec;36(4):465–476. [PubMed] [Google Scholar]
- Tuazon P. T., Merrick W. C., Traugh J. A. Comparative analysis of phosphorylation of translational initiation and elongation factors by seven protein kinases. J Biol Chem. 1989 Feb 15;264(5):2773–2777. [PubMed] [Google Scholar]
- Zelent A., Mendelsohn C., Kastner P., Krust A., Garnier J. M., Ruffenach F., Leroy P., Chambon P. Differentially expressed isoforms of the mouse retinoic acid receptor beta generated by usage of two promoters and alternative splicing. EMBO J. 1991 Jan;10(1):71–81. doi: 10.1002/j.1460-2075.1991.tb07922.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zimmer A., Zimmer A. Induction of a RAR beta 2-lacZ transgene by retinoic acid reflects the neuromeric organization of the central nervous system. Development. 1992 Dec;116(4):977–983. doi: 10.1242/dev.116.4.977. [DOI] [PubMed] [Google Scholar]
- de Thé H., Marchio A., Tiollais P., Dejean A. A novel steroid thyroid hormone receptor-related gene inappropriately expressed in human hepatocellular carcinoma. Nature. 1987 Dec 17;330(6149):667–670. doi: 10.1038/330667a0. [DOI] [PubMed] [Google Scholar]
- van der Leede B. J., Folkers G. E., Kruyt F. A., van der Saag P. T. Genomic organization of the human retinoic acid receptor beta 2. Biochem Biophys Res Commun. 1992 Oct 30;188(2):695–702. doi: 10.1016/0006-291x(92)91112-4. [DOI] [PubMed] [Google Scholar]
