Abstract
The synthesis of a number of enzymes of sulfur assimilation in Neurospora crassa is controlled by the sulfur source. Mutants in one regulatory gene, cys-3, are unable to make any of the enzymes. This locus is thought to specify a macromolecule that is required for the expression of the structural genes. A mutant, scon c, of another regulatory gene is nonrepressible for the synthesis of the enzymes. We report here the isolation of suppressed scon c strains which are actually the double mutant, scon c,cys-3. These strains are phenotypically indistinguishable from single mutants at the cys-3 locus. Thus cys-3 is epistatic to scon c. Evidence that the expression of the cys-3 gene is itself controlled is also presented.
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This work is supported by a Public Health Service grant, GM-08995, from the National Institute of General Medical Sciences. One of us (R.L.M.) is supported by a Public Health Service Career Development Award.
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Dietrich, P.S., Metzenberg, R.L. Metabolic suppressors of a regulatory mutant in Neurospora . Biochem Genet 8, 73–84 (1973). https://doi.org/10.1007/BF00485558
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DOI: https://doi.org/10.1007/BF00485558