Summary
The protein and repressor nature of two regulatory gene products inE. coli has been demonstrated, employing mutants with either amber or thermosensitive mutations. The regulatory genes are thecytR and thedeoR genes, both of which contribute to the regulation of the synthesis of nucleoside catabolizing enzymes.
Enzyme levels in strains with concurrent mutations in both regulatory genes are considerably higher than the sum of the levels in strains with acytR or adeo R mutation alone, indicating a certain co-operativity between the two repressor proteins.
The glucose repression of enzyme levels observed in the double regulatory mutant is similar to that found in acytR mutant, and much more pronounced than the glucose effect in adeo R mutant.
A model of the promoter-operator region in thedeo operon is proposed.
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Adhya, S., Gottesman, M., de Crombrupghe, B.: Release of polarity inEscherichia coli by geneN of phage γ: Termination and antitermination of transcription. Proc. nat. Acad. Sci. (Wash.)71, 2534–2538 (1974)
Ahmad, S. I., Pritchard, R. H.: A map of four genes specifying enzymes involved in catabolism of nucleosides and deoxynucleosides inEscherichia coli. Molec. gen. Genet.104, 351–356 (1969)
Ahmad, S. I., Pritchard, R. H.: A regulatory mutant affecting the synthesis of enzymes involved in the catabolism of nucleosides inEscherichia coli Molec. gen. Genet.111, 77–83 (1971)
Ahmad, S. I., Pritchard, R. H.: An operator constitutive mutant affecting the synthesis of two enzymes involved in the catabolism of nucleosides inEscherichia coli. Molec. gen. Genet.124, 321–329 (1973)
Albrechtsen, H. (unpublished).
Baumanis, G. E., Smirnov, Yu. V., Sukhlodoletz, V. V.: Production and study of polar mutants for nucleoside catabolism linked genes inEscherichia coli. Genetika10, 81–88 (1974)
Blank, J., Hoffee, P.: Regulatory mutants of thedeo regulon inSalmonella typhimurium. Molec. gen. Genet.116, 291–298 (1972)
Hammer-Jespersen, K., Munch-Petersen, A.: Mutants ofEscherichia coli unable to metabolize cytidine: Isolation and characterization. Molec. gen. Genet.126, 177–186 (1973)
Hammer-Jespersen, K., Munch-Petersen, A., Nygaard, P., Schwartz, M.: Induction of enzymes involved in the catabolism of deoxyribonucleosides and ribonucleosides inEscherichia coli K 12. Europ. J. Biochem.19, 533–538 (1971)
Lomax, M. S., Greenberg, R.: Characteristics of thedeo operon: Role in thymine utilization and sensitivity to deoxyribonucleosides. J. Bact.96, 501–514 (1968)
Monod, J., Cohen-Bazire, G., Cohn, M.: Sur la biosynthese de la beta-galactosidase (lactase) chezEscherichia coli. La specificite de l'induction. Biochim. biophys. Acta (Amst.)7, 585–599 (1961)
Munch-Petersen, A., Nygaard, P., Hammer-Jespersen, K., Fiil, N.: Mutants constitutive for nucleoside-catabolizing enzymes inEscherichia coli K 12. Isolation, characterization and mapping. Europ. J. Biochem.27, 208–215 (1972)
Nygaard, P.: Nucleoside-catabolizing enzymes inSalmonella typhimurium. Induction by ribonucleosides. Europ. J. Biochem.36, 267–272 (1973)
Reznikoff, W. S., Miller, J. H., Scaife, J. G., Beckwith, J. R.: A mechanism for repressor action. J. molec. Biol.43, 201–213 (1969)
Svenningsen, B.: Regulatedin vitro Synthesis of the Enzymes of thedeo Operon ofEscherichia coli. Properties of the DNA Directed System. Molec. gen. Genet.137, 289–304 (1975)
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Communicated by E. Bautz
Abbreviations and Symbols. Genes coding for: cytidine deaminase,cdd; uridine phosphorylase,udp; thymidine phosphorylase,ipp; purine nucleoside phosphorylase,pup; uridine kinase (=cytidine kinase),udk;Cyt R = regulatory gene forcdd, udp, dra, tpp, drm, andpup. Deo R regulatory gene fordra, tpp, drm, andpup. This regulatory gene is believed to be identical to thenuc R gene described by Ahmad and Pritchard (1971). We have chosen the namedeo R for the gene, since the gene cluster controlled by this regulatory gene was originally designated thedeo operon by Lomax and Greenberg (1968). The namedeo R is also in agreement with the nomenclature used by Blank and Hoffee (1972) for the corresponding gene inSalmoeeella typhimurium. cAMP: cyclic adenosine 3:5′-monophosphate. CRP, cyclic AMP receptor protein. dRib5P: deoxyribose 5-phosphate
Enzymes. Purine nucleoside phosphorylase or purine nucleoside: orthophosphate (deoxy) ribosyltransferase (EC 2.4.2.1); thymidine phosphorylase or thymidine: orthophosphate deoxyribosyltransferase (EC 2.4.2.4); uridine phosphorylase or uridine: orthophosphate ribosyltransferase (EC 2.4.2.3); cytidine deaminase or (deoxy)cytidine aminohydrolase (EC 3.5.4.5); deoxyriboaldolase or 2-deoxy-D-ribose-5-phosphate; acetaldehydelyase (EC 4.1.2.4); phosphodeoxyribomutase
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Hammer-Jespersen, K., Munch-Petersen, A. Multiple regulation of nucleoside catabolizing enzymes: Regulation of thedeo operon by thecytR anddeoR gene products. Molec. Gen. Genet. 137, 327–335 (1975). https://doi.org/10.1007/BF00703258
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DOI: https://doi.org/10.1007/BF00703258