Summary
The ornithine transaminase (EC.2.6.1.13) of Saccharomyces cerevisiae is induced by arginine, ornithine, and their analogs. Genetic regulatory elements which are involved in this induction process have been defined due to the isolation of specific mutants. Two classes of OTAse operator mutants have previously been described; three unlinked genes are presumed to code for a specific repressor, CARGR of both of the arginine catabolic enzymes, arginase, and ornithine transaminase. The level of transaminase of cells grown on ammonia plus arginine is much lower than it is when arginine is the sole nitrogen source. Ammonia thus seems to limit the amount of enzyme synthesized when arginine is present in the growth medium. Nevertheless, all attempts to disclose a nitrogen catabolite repression process in OTAse synthesis have failed; neither the action of mutations that release this regulation on arginase and other catabolic enzymes, nor the use of derepressing growth conditions, affect OTAse synthesis. A decrease of the cells' arginine pool when amonia or aminoacids (serine, glutamate) are added to arginine as a nitrogen nutrient results in a progressive reduction of transaminase synthesis. This suggests that arginine is the only physiological effector in those conditions: ammonia or some aminoacids would reduce the enzyme synthesis because of an inducer exclusion. The first stage of OTAse induction would then be operated by the CARGR repressor, and an additional regulatory element might take part in the full scale process. Preliminary data favoring the involvment of such an element are presented.
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Béchet, J., Grenson, M., Wiame, J.M.: Mutations affecting the repressibility of arginine biosynthetic enzymes in Saccharomyces cerevisiae. Eur. J. Biochem. 12, 31–39 (1970)
Béchet, J., Wiame, J.M., Grenson, M.: Mutations affectant la régulation de la synthèse de l'ornithine transcarbamylase chez Saccharomyces cerevisiae. Arch. Int. Physiol. Biochim. 73, 137–139 (1965)
Demerec, M., Adelberg, E.A., Clark, A.J., Hartmann, P.E.: A proposal for a uniform nomenclature in bacterial genetics. Genetics 54, 61–76 (1966)
Deschamps, J., Wiame, J.M.: Mating type effect on cis-mutations leading to constitutivity of ornithine transaminase in diploid cells of Saccharomyces cerevisiae. Genetics, in press (1979)
Dubois, E., Grenson, M., Wiame, J.M.: The participation of the anabolic glutamate dehydrogenase in the nitrogen catabolite repression of arginase in Saccharomyces cerevisiae. Eur. J. Biochem. 48, 603–616 (1974)
Dubois, E., Hiernaux, D., Grenson, M., Wiame, J.M.: Specific induction of catabolism and its relation to repression of biosynthesis in arginine metabolism of Saccharomyces cerevisiae. J. Mol. Biol. 122, 383–406 (1978)
Dubois, E., Vissers, S., Grenson, M., Wiame, J.M.: Glutamine and ammonia in nitrogen catabolite repression of Saccharomyces cerevisiae. Biochem. Biophys. Res. Commun. 75, 233–239 (1977)
Dubois, E., Wiame, J.M.: Catabolic synergism: a cooperation between the availability of substrate and the need for nitrogen in the regulation of arginine catabolism in Saccharomyces cerevisiae. Mol. Gen. Genet. 164, 275–283 (1978)
Grenson, M., Hou, C.: Ammonia inhibition of the general amino acid permease and its suppression in NADPH-specific glutamate dehydrogenaseless mutants of Saccharomyces cerevisiae. Biochem. Biophys. Res. Commun. 48, 748–765 (1972)
Messenguy, F., Penninckx, M., Wiame, J.M.: Interaction between arginase and ornithine carbamoyltransferase in Saccharomyces cerevisiae. Eur. J. Biochem. 22, 277–286 (1971)
Middelhoven, W.J.: The derepression of arginase and of ornithine transaminase in nitrogen-starved baker's yeast. Biochim. Biophys. Acta 156, 440–443 (1968)
Middelhoven, W.J.: Isolation and characterization of methylammonium-resistant mutants of Saccharomyces cerevisiae. with relieved nitrogen metabolite repression of allantoinase, arginase and ornithine transaminase synthesis. J. Gen. Microbiol. 100, 257–269 (1977)
Ramos, F., Thuriaux, P., Wiame, J.M., Béchet, J.: The participation of ornithine and citrulline in the regulation of arginine metabolism in Saccharomyces cerevisiae. Eur. J. Biochem. 12, 40–47 (1970)
Thuriaux, P., Ramos, F., Piérard, A., Grenson, M., Wiame, J.M.: Regulation of the carbamoylphosphate synthetase belonging to the arginine biosynthetic pathway of Saccharomyces cerevisiae. J. Mol. Biol. 67, 277–287 (1972)
Thuriaux, P., Ramos, F., Wiame, J.M., Grenson, M., Béchet, J.: Sur l'existence de gènes régulateurs affectant simultanément la synthèse des enzymes biosynthétiques et cataboliques de l'arginine chez Saccharomyces cerevisiae. Arch. Int. Physiol. Biochim. 76, 955–956 (1968)
Wiame, J.M.: The regulation of arginine metabolism in Saccharomyces cerevisiae. Exclusion mechanisms. In: Current topics in cellular regulation, Vol. 4 (B.L. Horecker and E.R. Stadtman, eds), pp. 1–38. New York: Academic Press 1971
Wiame, J.M.: The regulation of the biosynthesis and the degradation of arginine in Saccharomyces cerevisiae. Proc. of the Third Intern Specialized Symp. on Yeasts, part II, pp. 307–330. Helsinki: Otaniemi 1973
Wiame, J.M., Dubois, E.: Nonspecific induction of arginase in Saccharomyces cerevisiae. Biochemie 58, 207–211 (1976)
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Communicated by W. Gajewski
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Deschamps, J., Dubois, E. & Wiame, JM. L-ornithine transaminase synthesis in Saccharomyces cerevisiae: Regulation by inducer exclusion. Molec. Gen. Genet. 174, 225–232 (1979). https://doi.org/10.1007/BF00267794
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DOI: https://doi.org/10.1007/BF00267794