Abstract
The downstream box (DB) has been proposed to enhance translation of several mRNAs and to be a key element controlling the expression of cold-shocked mRNAs. However, the proposal that the DB exerts its effects through a base pairing interaction with the complementary anti-downstream box (antiDB) sequence (nt 1469-1483) located in the penultimate stem (helix 44) of 16S rRNA remains controversial. The existence of this interaction during initiation of protein synthesis under cold-shock conditions has been investigated in the present work using an Escherichia coli strain whose ribosomes lack the potential to base pair with mRNA because of a 12 bp inversion of the antiDB sequence in helix 44. Our results show that this strain is capable of cold acclimation, withstands cold shock, and its ribosomes translate mRNAs that contain or lack DB sequences with similar efficiency, comparable to that of the wild type. The structure of helix 44 in 30S ribosomal subunits from cells grown at 37 degrees C and from cells subjected to cold shock was also analyzed by binding a 32P-labeled oligonucleotide complementary to the antiDB region and by chemical probing with DMS and kethoxal. Both approaches clearly indicate that this region is in a double-stranded conformation and therefore not available for base pairing with mRNA.
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- Asai T., Zaporojets D., Squires C., Squires C. L. An Escherichia coli strain with all chromosomal rRNA operons inactivated: complete exchange of rRNA genes between bacteria. Proc Natl Acad Sci U S A. 1999 Mar 2;96(5):1971–1976. doi: 10.1073/pnas.96.5.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brandi A., Pietroni P., Gualerzi C. O., Pon C. L. Post-transcriptional regulation of CspA expression in Escherichia coli. Mol Microbiol. 1996 Jan;19(2):231–240. doi: 10.1046/j.1365-2958.1996.362897.x. [DOI] [PubMed] [Google Scholar]
- Calogero R. A., Pon C. L., Canonaco M. A., Gualerzi C. O. Selection of the mRNA translation initiation region by Escherichia coli ribosomes. Proc Natl Acad Sci U S A. 1988 Sep;85(17):6427–6431. doi: 10.1073/pnas.85.17.6427. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Etchegaray J. P., Inouye M. DB or not DB in translation? Mol Microbiol. 1999 Jul;33(2):438–439. doi: 10.1046/j.1365-2958.1999.01487.x. [DOI] [PubMed] [Google Scholar]
- Etchegaray J. P., Inouye M. Translational enhancement by an element downstream of the initiation codon in Escherichia coli. J Biol Chem. 1999 Apr 9;274(15):10079–10085. doi: 10.1074/jbc.274.15.10079. [DOI] [PubMed] [Google Scholar]
- Firpo M. A., Dahlberg A. E. The importance of base pairing in the penultimate stem of Escherichia coli 16S rRNA for ribosomal subunit association. Nucleic Acids Res. 1998 May 1;26(9):2156–2160. doi: 10.1093/nar/26.9.2156. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldenberg D., Azar I., Oppenheim A. B., Brandi A., Pon C. L., Gualerzi C. O. Role of Escherichia coli cspA promoter sequences and adaptation of translational apparatus in the cold shock response. Mol Gen Genet. 1997 Oct;256(3):282–290. doi: 10.1007/s004380050571. [DOI] [PubMed] [Google Scholar]
- Gualerzi C. O., Pon C. L. Initiation of mRNA translation in prokaryotes. Biochemistry. 1990 Jun 26;29(25):5881–5889. doi: 10.1021/bi00477a001. [DOI] [PubMed] [Google Scholar]
- Jones P. G., Mitta M., Kim Y., Jiang W., Inouye M. Cold shock induces a major ribosomal-associated protein that unwinds double-stranded RNA in Escherichia coli. Proc Natl Acad Sci U S A. 1996 Jan 9;93(1):76–80. doi: 10.1073/pnas.93.1.76. [DOI] [PMC free article] [PubMed] [Google Scholar]
- La Teana A., Pon C. L., Gualerzi C. O. Translation of mRNAs with degenerate initiation triplet AUU displays high initiation factor 2 dependence and is subject to initiation factor 3 repression. Proc Natl Acad Sci U S A. 1993 May 1;90(9):4161–4165. doi: 10.1073/pnas.90.9.4161. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCarthy J. E., Gualerzi C. Translational control of prokaryotic gene expression. Trends Genet. 1990 Mar;6(3):78–85. doi: 10.1016/0168-9525(90)90098-q. [DOI] [PubMed] [Google Scholar]
- Merryman C., Moazed D., McWhirter J., Noller H. F. Nucleotides in 16S rRNA protected by the association of 30S and 50S ribosomal subunits. J Mol Biol. 1999 Jan 8;285(1):97–105. doi: 10.1006/jmbi.1998.2242. [DOI] [PubMed] [Google Scholar]
- Mitta M., Fang L., Inouye M. Deletion analysis of cspA of Escherichia coli: requirement of the AT-rich UP element for cspA transcription and the downstream box in the coding region for its cold shock induction. Mol Microbiol. 1997 Oct;26(2):321–335. doi: 10.1046/j.1365-2958.1997.5771943.x. [DOI] [PubMed] [Google Scholar]
- Moazed D., Noller H. F. Transfer RNA shields specific nucleotides in 16S ribosomal RNA from attack by chemical probes. Cell. 1986 Dec 26;47(6):985–994. doi: 10.1016/0092-8674(86)90813-5. [DOI] [PubMed] [Google Scholar]
- Morita M., Kanemori M., Yanagi H., Yura T. Heat-induced synthesis of sigma32 in Escherichia coli: structural and functional dissection of rpoH mRNA secondary structure. J Bacteriol. 1999 Jan;181(2):401–410. doi: 10.1128/jb.181.2.401-410.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mueller F., Stark H., van Heel M., Rinke-Appel J., Brimacombe R. A new model for the three-dimensional folding of Escherichia coli 16 S ribosomal RNA. III. The topography of the functional centre. J Mol Biol. 1997 Aug 29;271(4):566–587. doi: 10.1006/jmbi.1997.1212. [DOI] [PubMed] [Google Scholar]
- Nagai H., Yuzawa H., Yura T. Interplay of two cis-acting mRNA regions in translational control of sigma 32 synthesis during the heat shock response of Escherichia coli. Proc Natl Acad Sci U S A. 1991 Dec 1;88(23):10515–10519. doi: 10.1073/pnas.88.23.10515. [DOI] [PMC free article] [PubMed] [Google Scholar]
- O'Connor M., Asai T., Squires C. L., Dahlberg A. E. Enhancement of translation by the downstream box does not involve base pairing of mRNA with the penultimate stem sequence of 16S rRNA. Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8973–8978. doi: 10.1073/pnas.96.16.8973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Odjakova M., Golshani A., Ivanov G., Abou Haidar M., Ivanov I. The low level expression of chloramphenicol acetyltransferase (CAT) mRNA in Escherichia coli is not dependent on either Shine-Dalgarno or the downstream boxes in the CAT gene. Microbiol Res. 1998 Aug;153(2):173–178. doi: 10.1016/S0944-5013(98)80037-2. [DOI] [PubMed] [Google Scholar]
- Ohsawa H., Gualerzi C. Chemical modification in situ of Escherichia coli 30 S ribosomal proteins by the site-specific reagent pyridoxal phosphate. Inactivation of the aminoacyl-tRNA and mRNA binding sites. J Biol Chem. 1983 Jan 10;258(1):150–156. [PubMed] [Google Scholar]
- Resch A., Tedin K., Gründling A., Mündlein A., Bläsi U. Downstream box-anti-downstream box interactions are dispensable for translation initiation of leaderless mRNAs. EMBO J. 1996 Sep 2;15(17):4740–4748. [PMC free article] [PubMed] [Google Scholar]
- Rocha E. P., Danchin A., Viari A. Translation in Bacillus subtilis: roles and trends of initiation and termination, insights from a genome analysis. Nucleic Acids Res. 1999 Sep 1;27(17):3567–3576. doi: 10.1093/nar/27.17.3567. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shapira S. K., Chou J., Richaud F. V., Casadaban M. J. New versatile plasmid vectors for expression of hybrid proteins coded by a cloned gene fused to lacZ gene sequences encoding an enzymatically active carboxy-terminal portion of beta-galactosidase. Gene. 1983 Nov;25(1):71–82. doi: 10.1016/0378-1119(83)90169-5. [DOI] [PubMed] [Google Scholar]
- Shean C. S., Gottesman M. E. Translation of the prophage lambda cl transcript. Cell. 1992 Aug 7;70(3):513–522. doi: 10.1016/0092-8674(92)90175-c. [DOI] [PubMed] [Google Scholar]
- Sprengart M. L., Fuchs E., Porter A. G. The downstream box: an efficient and independent translation initiation signal in Escherichia coli. EMBO J. 1996 Feb 1;15(3):665–674. [PMC free article] [PubMed] [Google Scholar]
- Sprengart M. L., Porter A. G. Functional importance of RNA interactions in selection of translation initiation codons. Mol Microbiol. 1997 Apr;24(1):19–28. doi: 10.1046/j.1365-2958.1997.3161684.x. [DOI] [PubMed] [Google Scholar]