Summary
The uxuAB operon is under the dual control of uxuR- and exuR-encoded repressors whereas the exu regulon genes are regulated by the sole ExuR repressor. Mutations affecting the two exuR and uxuR regulatory genes were selected to investigate the relationship between the two repressors. The isolation of exuR and uxuR negative dominant mutations on a multicopy plasmid indicated that the active form of the two repressors was multimeric.
The introduction of a uxuR negative dominant allele into a wild-type strain resulted in a significant increase in exu gene expression. This unexpected effect may have been the consequence of the formation of hybrid repressor molecules. This protein must be composed of native ExuR+ subunits aggregated with altered UxuR subunits. The same interference was observed for the exuR negative dominant allele on uxu gene derepression. The hypothesis given here implies that the two regions of the ExuR and UxuR repressors involved in the subunit aggregation present enough homologies to allow the formation of hybrid repressor molecules.
Similar content being viewed by others
References
Adler K, Beyreuther K, Fanning E, Geisler N, Gronenborn B, Klemm A, Müller-Hill B, Pfahl M, Schmitz A (1972) How lac repressor binds to DNA. Nature 237:322–327
Ashwell G (1962). Enzymes of glucuronic and galacturonic acid metabolism in bacteria. Methods Enzymol 5:190–208
Birnboim HC, Doly J (1979). A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acid Res 7:1513–1524
Bolivar F, Rodriguez RL, Greene PJ, Betlach MC, Heynecker HL, Boyer HW, Crosa JH, Falkow S (1977). Construction and characterization of new cloning vehicles. II A multipurpose cloning system. Gene 2:95–113
Casadaban MJ (1976) Transposition and fusion of the lac genes to selected promoters in Escherichia coli using bacteriophage lambda and Mu. J Mol Biol 104:541–555
Coulondre C, Miller JH (1977) Genetic studies of the lac repressor. IV Mutagenic specificity in the lacI gene of Escherichia coli. J Mol Biol 117:577–606
Eilen E, Krakow JS (1977) Cyclic AMP-mediated intersubunit disulfide crosslinking of the cyclic AMP receptor protein of Escherichia coli. J Mol Biol 114:47–60
Guerry P, Le Blanc DJ, Falkow S (1973) General method for the isolation of plasmid deoxyribonucleic acid. J Bacteriol 116:1064–1066
Gunsalus RP, Yanofsky C (1980) Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor. Proc Natl Acad Sci USA 77:7112–7121
Hugouvieux-Cotte-Pattat N, Robert-Baudouy J (1982). Regulation and transcription direction of exuR, a self-regulated repressor in Escherichia coli K-12. J Mol Biol 156:221–228
Mandel M, Higa H (1970) Calcium-dependent bacteriophage DNA infection. J Mol Biol 53:159–162
Maniatis T, Jeffrey A, Van de Sande H (1975) Chain length determination of small double- and single-stranded DNA molecules by polyacrylamide gel electrophoresis. Biochemistry 14:3787–3794
Mata M, Delstanche M, Robert-Baudouy J (1978) Isolation of specialized transducing bacteriophages carrying the structural genes of hexuronate system in Escherichia coli K-12: exu region. J Bacteriol 133:549–557
Mata-Gilsinger M, Ritzenthaler P, Blanco C (1983) Characterization of the operator sites of the exu regulon in Escherichia coli K-12 by operator-constitutive mutations and repressor titration. Genetics 105:829–842
Miller J (1972) Experiments in molecular genetics. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
Müller-Hill B (1975) lac repressor and lac operator. Prog Biophys Mol Biol 30:227–252
Müller-Hill B, Crapo L, Gilbert W (1968) Mutants that make more lac repressor. Proc Natl Acad Sci USA 59:1259–1264
Novel M, Novel G (1976) Regulation of β-glucuronidase synthesis in Escherichia coli K-12: constitutive mutants specifically derepressed for uidA expression. J Bacteriol 127:406–417
Portalier R, Stoeber F (1972a) La D-altronate: NAD+ oxydoreductase d'Escherichia coli K-12: purification, propriétés et individualité. Eur J Biochem 26:50–61
Portalier R, Stoeber F (1972b) Dosages colorimétriques des oxydoréductases aldoniques d'E. coli K-12: applications. Biochim Biophys Acta 289:19–27
Radloff R, Bauer W, Vinograd J (1967) A dye-buoyant density method for the detection and isolation of closed circular duplex DNA: the closed circular DNA in HeLa cells. Proc Nat Acad Sci USA 57:1514–1521
Ritzenthaler P, Mata-Gilsinger M (1982) Use of in vitro gene fusions to study the uxuR regulatory gene in Escherichia coli K-12: direction of transcription and regulation of its expression. J Bacteriol 150:1040–1047
Ritzenthaler P, Mata-Gilsinger M (1983) Multiple regulation involved in the expression of the uxuR regulatory gene in Escherichia coli K-12. Mol Gen Genet 189:351–354
Ritzenthaler P, Mata-Gilsinger M, Stoeber F (1980) Construction and expression of hybrid plasmids containing Escherichia coli K-12 uxu genes. J Bacteriol 143:1116–1126
Ritzenthaler P, Mata-Gilsinger M, Stoeber F (1981) Molecular cloning of Escherichia coli K-12 hexuronate system genes: exu region. J Bacteriol 145:181–190
Ritzenthaler P, Blanco C, Mata-Gilsinger M (1983) Interchangeability of repressors for the control of the uxu and uid operons in E. coli K-12. Mol Gen Genet 191:263–270
Robert-Baudouy J, Portalier R, Stoeber F (1981) Regulation of hexuronate system genes in Escherichia coli K-12: multiple regulation of the uxu operon by exuR and uxuR gene products. J Bacteriol 145:211–230
Steffen D, Schleif R (1977) Overproducing araC with lambda-arabinose transducing phage. Mol Gen Genet 157:333–339
Takeda Y, Folkmanis A, Echols H (1979) cro regulatory protein specified by bacteriophage λ. J Biol Chem 252:6177–6183
Tessman I (1968) Mutagenic treatment of double- and singlestranded DNA phages T4 and S13 with hydroxylamine. Virology 35:330–333
Weber K, Files JG, Platt T, Ganem D, Miller JH (1975). Lac repressor. In: Sund H, Blauer G (eds) Protein-ligand interactions. De Gruyter, Berlin, pp 228–237
Author information
Authors and Affiliations
Additional information
Communicated by P. Starlinger
Rights and permissions
About this article
Cite this article
Ritzenthaler, P., Blanco, C. & Mata-Gilsinger, M. Genetic analysis of uxuR and exuR genes: evidence for ExuR and UxuR monomer repressors interactions. Mol Gen Genet 199, 507–511 (1985). https://doi.org/10.1007/BF00330766
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00330766