Isolation of Aspergillus Niger creA Mutants and Effects of the Mutations on Expression of Arabinases and L-arabinose Catabolic Enzymes

Microbiology. 1997 Sep;143 ( Pt 9):2991-8. doi: 10.1099/00221287-143-9-2991.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabinose / metabolism
  • Aspergillus niger / genetics*
  • Aspergillus niger / growth & development
  • Aspergillus niger / metabolism*
  • Chromosome Mapping
  • Fungal Proteins / genetics*
  • Gene Expression
  • Genes, Fungal
  • Glucose / metabolism
  • Glycoside Hydrolases / genetics*
  • Glycoside Hydrolases / metabolism
  • Mutation*
  • Phenotype
  • Repressor Proteins / genetics*
  • gamma-Aminobutyric Acid / metabolism

Substances

  • Fungal Proteins
  • Repressor Proteins
  • CreA protein, Aspergillus nidulans
  • gamma-Aminobutyric Acid
  • Arabinose
  • Glycoside Hydrolases
  • alpha-N-arabinofuranosidase
  • arabinan endo-1,5-alpha-L-arabinosidase
  • Glucose