Abstract
In addition to being a component of the large ribosomal subunit, ribosomal protein L20 of Escherichia coli also acts as a translational repressor. L20 is synthesized from the IF3 operon that contains three cistrons coding for IF3, and ribosomal proteins L35 and L20. L20 directly represses the expression of the gene encoding L35 and the expression of its own gene by translational coupling. All of the cis-acting sequences required for repression by L20, called the operator, are found on an mRNA segment extending from the middle of the IF3 gene to the start of the L35 gene. L20-mediated repression requires a long-range base-pairing interaction between nucleotide residues within the IF3 gene and residues just upstream of the L35 gene. This interaction results in the formation of a pseudoknot. Here we show that L20 causes protection of nucleotide residues in two regions of the operator in vitro. The first region is the pseudoknot itself and the second lies in an irregular stem located upstream of the L35 gene. By primer extension analysis, we show that L20 specifically induces reverse transcriptase stops in both regions. Therefore, these two regions define two L20-binding sites in the operator. Using mutations and deletions of rpml'-'lacZ fusions, we show that both sites are essential for repression in vivo. However L20 can bind to each site independently in vitro. One site is similar to the L20-binding site on 23S rRNA. Here we propose that L20 recognizes its mRNA and its rRNA in similar way.
Full Text
The Full Text of this article is available as a PDF (710.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brunel C., Caillet J., Lesage P., Graffe M., Dondon J., Moine H., Romby P., Ehresmann C., Ehresmann B., Grunberg-Manago M. Domains of the Escherichia coli threonyl-tRNA synthetase translational operator and their relation to threonine tRNA isoacceptors. J Mol Biol. 1992 Oct 5;227(3):621–634. doi: 10.1016/0022-2836(92)90212-3. [DOI] [PubMed] [Google Scholar]
- Butler J. S., Springer M., Dondon J., Graffe M., Grunberg-Manago M. Escherichia coli protein synthesis initiation factor IF3 controls its own gene expression at the translational level in vivo. J Mol Biol. 1986 Dec 20;192(4):767–780. doi: 10.1016/0022-2836(86)90027-6. [DOI] [PubMed] [Google Scholar]
- Chiaruttini C., Milet M., Springer M. A long-range RNA-RNA interaction forms a pseudoknot required for translational control of the IF3-L35-L20 ribosomal protein operon in Escherichia coli. EMBO J. 1996 Aug 15;15(16):4402–4413. [PMC free article] [PubMed] [Google Scholar]
- Gregory R. J., Cahill P. B., Thurlow D. L., Zimmermann R. A. Interaction of Escherichia coli ribosomal protein S8 with its binding sites in ribosomal RNA and messenger RNA. J Mol Biol. 1988 Nov 20;204(2):295–307. doi: 10.1016/0022-2836(88)90577-3. [DOI] [PubMed] [Google Scholar]
- Harms J., Schluenzen F., Zarivach R., Bashan A., Gat S., Agmon I., Bartels H., Franceschi F., Yonath A. High resolution structure of the large ribosomal subunit from a mesophilic eubacterium. Cell. 2001 Nov 30;107(5):679–688. doi: 10.1016/s0092-8674(01)00546-3. [DOI] [PubMed] [Google Scholar]
- Köhrer C., Mayer C., Neumair O., Gröbner P., Piendl W. Interaction of ribosomal L1 proteins from mesophilic and thermophilic Archaea and Bacteria with specific L1-binding sites on 23S rRNA and mRNA. Eur J Biochem. 1998 Aug 15;256(1):97–105. doi: 10.1046/j.1432-1327.1998.2560097.x. [DOI] [PubMed] [Google Scholar]
- Lesage P., Chiaruttini C., Graffe M., Dondon J., Milet M., Springer M. Messenger RNA secondary structure and translational coupling in the Escherichia coli operon encoding translation initiation factor IF3 and the ribosomal proteins, L35 and L20. J Mol Biol. 1992 Nov 20;228(2):366–386. doi: 10.1016/0022-2836(92)90827-7. [DOI] [PubMed] [Google Scholar]
- Lesage P., Truong H. N., Graffe M., Dondon J., Springer M. Translated translational operator in Escherichia coli. Auto-regulation in the infC-rpmI-rplT operon. J Mol Biol. 1990 Jun 5;213(3):465–475. doi: 10.1016/S0022-2836(05)80208-6. [DOI] [PubMed] [Google Scholar]
- Nomura M., Gourse R., Baughman G. Regulation of the synthesis of ribosomes and ribosomal components. Annu Rev Biochem. 1984;53:75–117. doi: 10.1146/annurev.bi.53.070184.000451. [DOI] [PubMed] [Google Scholar]
- Nomura M., Yates J. L., Dean D., Post L. E. Feedback regulation of ribosomal protein gene expression in Escherichia coli: structural homology of ribosomal RNA and ribosomal protein MRNA. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7084–7088. doi: 10.1073/pnas.77.12.7084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Said B., Cole J. R., Nomura M. Mutational analysis of the L1 binding site of 23S rRNA in Escherichia coli. Nucleic Acids Res. 1988 Nov 25;16(22):10529–10545. doi: 10.1093/nar/16.22.10529. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schatz D., Leberman R., Eckstein F. Interaction of Escherichia coli tRNA(Ser) with its cognate aminoacyl-tRNA synthetase as determined by footprinting with phosphorothioate-containing tRNA transcripts. Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):6132–6136. doi: 10.1073/pnas.88.14.6132. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Springer M., Graffe M., Butler J. S., Grunberg-Manago M. Genetic definition of the translational operator of the threonine-tRNA ligase gene in Escherichia coli. Proc Natl Acad Sci U S A. 1986 Jun;83(12):4384–4388. doi: 10.1073/pnas.83.12.4384. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Springer M., Plumbridge J. A., Butler J. S., Graffe M., Dondon J., Mayaux J. F., Fayat G., Lestienne P., Blanquet S., Grunberg-Manago M. Autogenous control of Escherichia coli threonyl-tRNA synthetase expression in vivo. J Mol Biol. 1985 Sep 5;185(1):93–104. doi: 10.1016/0022-2836(85)90185-8. [DOI] [PubMed] [Google Scholar]
- Wower I., Kowaleski M. P., Sears L. E., Zimmermann R. A. Mutagenesis of ribosomal protein S8 from Escherichia coli: defects in regulation of the spc operon. J Bacteriol. 1992 Feb;174(4):1213–1221. doi: 10.1128/jb.174.4.1213-1221.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu H., Jiang L., Zimmermann R. A. The binding site for ribosomal protein S8 in 16S rRNA and spc mRNA from Escherichia coli: minimum structural requirements and the effects of single bulged bases on S8-RNA interaction. Nucleic Acids Res. 1994 May 11;22(9):1687–1695. doi: 10.1093/nar/22.9.1687. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zengel J. M., Lindahl L. Diverse mechanisms for regulating ribosomal protein synthesis in Escherichia coli. Prog Nucleic Acid Res Mol Biol. 1994;47:331–370. doi: 10.1016/s0079-6603(08)60256-1. [DOI] [PubMed] [Google Scholar]