Skip to main content
NCBI home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1984 Feb;157(2):363–367. doi: 10.1128/jb.157.2.363-367.1984

Translational coupling of the trpB and trpA genes in the Escherichia coli tryptophan operon.

S Aksoy, C L Squires, C Squires
PMCID: PMC215255  PMID: 6319355

Abstract

We investigated whether there is translational coupling between the tryptophan operon trpB and trpA genes in Escherichia coli. A trp-lac fusion system was used in which part of the trpA gene is fused to the lacZ gene. This fusion protein has the translation initiation site of trpA but retains beta-galactosidase activity. We introduced a frameshift mutation early in trpB and measured its effect on transcription and translation of the trp-lac fusion. The mutation resulted in a 10-fold drop in beta-galactosidase activity but only a 2-fold drop in lacZ mRNA or galactoside transacetylase levels. An rho mutation restored the lacZ mRNA and transacetylase levels to those of the control but only increased the beta-galactosidase level to 20% that of the control. We conclude from these results that if the trpB gene is not translated, efficient translation of the trpA'-lac'Z mRNA does not occur and, thus, that these genes are translationally coupled. The implication of this finding for other studies with gene fusions is discussed.

Full text

PDF
363

Images in this article

366Image
on p.366

Selected References

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

  1. Adhya S., Gottesman M. Control of transcription termination. Annu Rev Biochem. 1978;47:967–996. doi: 10.1146/annurev.bi.47.070178.004535. [DOI] [PubMed] [Google Scholar]
  2. Barry G., Squires C. L., Squires C. Control features within the rplJL-rpoBC transcription unit of Escherichia coli. Proc Natl Acad Sci U S A. 1979 Oct;76(10):4922–4926. doi: 10.1073/pnas.76.10.4922. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Barry G., Squires C., Squires C. L. Attenuation and processing of RNA from the rplJL--rpoBC transcription unit of Escherichia coli. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3331–3335. doi: 10.1073/pnas.77.6.3331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Baughman G., Nomura M. Localization of the target site for translational regulation of the L11 operon and direct evidence for translational coupling in Escherichia coli. Cell. 1983 Oct;34(3):979–988. doi: 10.1016/0092-8674(83)90555-x. [DOI] [PubMed] [Google Scholar]
  5. Birnboim H. C., Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979 Nov 24;7(6):1513–1523. doi: 10.1093/nar/7.6.1513. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bogenhagen D. F., Sakonju S., Brown D. D. A control region in the center of the 5S RNA gene directs specific initiation of transcription: II. The 3' border of the region. Cell. 1980 Jan;19(1):27–35. doi: 10.1016/0092-8674(80)90385-2. [DOI] [PubMed] [Google Scholar]
  7. Casadaban M. J., Chou J., Cohen S. N. In vitro gene fusions that join an enzymatically active beta-galactosidase segment to amino-terminal fragments of exogenous proteins: Escherichia coli plasmid vectors for the detection and cloning of translational initiation signals. J Bacteriol. 1980 Aug;143(2):971–980. doi: 10.1128/jb.143.2.971-980.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Casadaban M. J., Cohen S. N. Analysis of gene control signals by DNA fusion and cloning in Escherichia coli. J Mol Biol. 1980 Apr;138(2):179–207. doi: 10.1016/0022-2836(80)90283-1. [DOI] [PubMed] [Google Scholar]
  9. Casadaban M. J., Cohen S. N. Lactose genes fused to exogenous promoters in one step using a Mu-lac bacteriophage: in vivo probe for transcriptional control sequences. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4530–4533. doi: 10.1073/pnas.76.9.4530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Cerretti D. P., Dean D., Davis G. R., Bedwell D. M., Nomura M. The spc ribosomal protein operon of Escherichia coli: sequence and cotranscription of the ribosomal protein genes and a protein export gene. Nucleic Acids Res. 1983 May 11;11(9):2599–2616. doi: 10.1093/nar/11.9.2599. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Cohen S. N., Chang A. C., Hsu L. Nonchromosomal antibiotic resistance in bacteria: genetic transformation of Escherichia coli by R-factor DNA. Proc Natl Acad Sci U S A. 1972 Aug;69(8):2110–2114. doi: 10.1073/pnas.69.8.2110. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Fiandt M., Szybalski W., Malamy M. H. Polar mutations in lac, gal and phage lambda consist of a few IS-DNA sequences inserted with either orientation. Mol Gen Genet. 1972;119(3):223–231. doi: 10.1007/BF00333860. [DOI] [PubMed] [Google Scholar]
  13. Guterman S. K., Howitt C. L. Rifampicin supersensitivity of rho strains of E. coli, and suppression by sur mutation. Mol Gen Genet. 1979 Jan 16;169(1):27–34. doi: 10.1007/BF00267541. [DOI] [PubMed] [Google Scholar]
  14. Imamoto F., Yanofsky C. Transcription of the tryptophan operon in polarity mutants of Escherichia coli. I. Characterization of the tryptophan messenger RNA of polar mutants. J Mol Biol. 1967 Aug 28;28(1):1–23. doi: 10.1016/s0022-2836(67)80073-1. [DOI] [PubMed] [Google Scholar]
  15. McKenney K., Shimatake H., Court D., Schmeissner U., Brady C., Rosenberg M. A system to study promoter and terminator signals recognized by Escherichia coli RNA polymerase. Gene Amplif Anal. 1981;2:383–415. [PubMed] [Google Scholar]
  16. Messing J., Crea R., Seeburg P. H. A system for shotgun DNA sequencing. Nucleic Acids Res. 1981 Jan 24;9(2):309–321. doi: 10.1093/nar/9.2.309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Morse D. E., Yanofsky C. Polarity and the degradation of mRNA. Nature. 1969 Oct 25;224(5217):329–331. doi: 10.1038/224329a0. [DOI] [PubMed] [Google Scholar]
  18. Oppenheim D. S., Yanofsky C. Translational coupling during expression of the tryptophan operon of Escherichia coli. Genetics. 1980 Aug;95(4):785–795. doi: 10.1093/genetics/95.4.785. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Post L. E., Strycharz G. D., Nomura M., Lewis H., Dennis P. P. Nucleotide sequence of the ribosomal protein gene cluster adjacent to the gene for RNA polymerase subunit beta in Escherichia coli. Proc Natl Acad Sci U S A. 1979 Apr;76(4):1697–1701. doi: 10.1073/pnas.76.4.1697. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Reznikoff W. S., Michels C. A., Cooper T. G., Silverstone A. E., Magasanik B. Inhibition of lacZ gene translation initiation in trp-lac fusion strains. J Bacteriol. 1974 Mar;117(3):1231–1239. doi: 10.1128/jb.117.3.1231-1239.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Salser W., Gesteland R. F., Bolle A. In vitro synthesis of bacteriophage lysozyme. Nature. 1967 Aug 5;215(5101):588–591. doi: 10.1038/215588a0. [DOI] [PubMed] [Google Scholar]
  22. Schümperli D., McKenney K., Sobieski D. A., Rosenberg M. Translational coupling at an intercistronic boundary of the Escherichia coli galactose operon. Cell. 1982 Oct;30(3):865–871. doi: 10.1016/0092-8674(82)90291-4. [DOI] [PubMed] [Google Scholar]
  23. Squires C., Krainer A., Barry G., Shen W. F., Squires C. L. Nucleotide sequence at the end of the gene for the RNA polymerase beta' subunit (rpoC). Nucleic Acids Res. 1981 Dec 21;9(24):6827–6840. doi: 10.1093/nar/9.24.6827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Yanofsky C., Platt T., Crawford I. P., Nichols B. P., Christie G. E., Horowitz H., VanCleemput M., Wu A. M. The complete nucleotide sequence of the tryptophan operon of Escherichia coli. Nucleic Acids Res. 1981 Dec 21;9(24):6647–6668. doi: 10.1093/nar/9.24.6647. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Yates J. L., Nomura M. Feedback regulation of ribosomal protein synthesis in E. coli: localization of the mRNA target sites for repressor action of ribosomal protein L1. Cell. 1981 Apr;24(1):243–249. doi: 10.1016/0092-8674(81)90520-1. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES