At least four regulatory genes control sulphur metabolite repression in Aspergillus nidulans.
Mutations in four genes: sconA (formerly suA25meth, mapA25), sconB (formerly mapB1), sconC and sconD, the last two identified in this work, relieve a group of sulphur amino acid biosynthetic enzymes from methionine-mediated sulphur metabolite repression. Exogenous methionine has no effect on sulphate assimilation in the mutant strains, whereas in the wild type it causes almost complete elimination of sulphate incorporation. In both mutant and wild-type strains methionine is efficiently taken up and metabolized to S-adenosylmethionine, homocysteine and other compounds, scon mutants also show elevated levels of folate-metabolizing enzymes which results from the large pool of homocysteine found in these strains. The folate enzymes appear to be inducible by homocysteine and repressible by methionine (or S-adenosylmethionine).
Natorff
R
R
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw.
Balińska
M
M
Paszewski
A
A
D001192:Arylsulfatases / Q000235:genetics; D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics*; D019757:Carbon-Oxygen Lyases; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D003433:Crosses, Genetic; D003547:Cysteine Synthase; D005800:Genes, Fungal; D005809:Genes, Regulator; D016153:Genes, Suppressor; D008040:Genetic Linkage; D006710:Homocysteine / Q000378:metabolism; D008190:Lyases / Q000235:genetics; D008715:Methionine / Q000378:metabolism*; D009097:Multienzyme Complexes; D012436:S-Adenosylmethionine / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013430:Sulfate Adenylyltransferase / Q000235:genetics; D013455:Sulfur / Q000378:metabolism*
D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D006710:Homocysteine; D013455:Sulfur; D012436:S-Adenosylmethionine; D008715:Methionine; D003547:Cysteine Synthase; C103381:MET17 protein, S cerevisiae; C018725:O-acetylhomoserine (thiol)-lyase; D013430:Sulfate Adenylyltransferase; D001192:Arylsulfatases; D008190:Lyases; D019757:Carbon-Oxygen Lyases; C019965:cystathionine beta-lyase