title: Isolation of Aspergillus niger creA mutants and effects of the mutations on expression of arabinases and L-arabinose catabolic enzymes.
abstract: Aspergillus niger mutants relieved of carbon repression were isolated from an areA parental strain by selection of colonies that exhibited improved growth on a combination of 4-aminobutanoic acid (GABA) and D-glucose. In addition to derepression of the utilization of GABA as a nitrogen source in the presence of D-glucose, three of the four mutants also showed derepression of L-alanine and L-proline utilization. Transformation of the mutants with the A. niger creA gene, encoding the repressor protein CREA, re-established the areA phenotype on GABA/D-glucose, identifying the mutations as creAd. The creA gene mapped on chromosome IV by linkage analysis and contour-clamped homogeneous electric field hybridization. The creA mutants obtained were used to study the involvement of CREA in repression by D-glucose of arabinases and L-arabinose catabolism in A. niger. In wild-type A. niger, alpha-L-arabinofuranosidase A, alpha-L-arabinofuranosidase B, endo-arabinase, L-arabinose reductase and L-arabitol dehydrogenase were induced on L-arabinose, but addition of D-glucose prevented this induction. Repression was relieved to varying degrees in the creA mutants, showing that biosynthesis of arabinases and L-arabinose catabolic enzymes is under control of CREA.
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: George J G
authors.initials: GJG
authors.lastname: Ruijter
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: Sipo A
authors.initials: SA
authors.lastname: Vanhanen
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: Marco M C
authors.initials: MMC
authors.lastname: Gielkens
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: Peter J I
authors.initials: PJI
authors.lastname: van de Vondervoort
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: Jaap
authors.initials: J
authors.lastname: Visser
mesh_terms: D001089:Arabinose / Q000378:metabolism; D001234:Aspergillus niger / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D002874:Chromosome Mapping; D005656:Fungal Proteins / Q000235:genetics*; D015870:Gene Expression; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D012097:Repressor Proteins / Q000235:genetics*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D012097:Repressor Proteins; C071237:CreA protein, Aspergillus nidulans; D005680:gamma-Aminobutyric Acid; D001089:Arabinose; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase; C082526:arabinan endo-1,5-alpha-L-arabinosidase; D005947:Glucose