The Aspergillus nidulans gltA gene encoding glutamate synthase is required for ammonium assimilation in the absence of NADP-glutamate dehydrogenase

Curr Genet. 1999 Jan;34(6):467-71. doi: 10.1007/s002940050421.

Abstract

Mutants of Aspergillus nidulans lacking NADP-glutamate dehydrogenase activity grow more poorly than wild-type strains on ammonium as a sole nitrogen source. The leaky growth of these mutants is indicative of an alternative pathway of ammonium assimilation and glutamate biosynthesis. We have PCR-amplified a portion of the A. nidulans gene encoding glutamate synthase and used this sequence to inactivate the genomic copy. This gene, designated gltA, was found to be dispensable for growth on ammonium in the presence of NADP-glutamate dehydrogenase activity. However, a strain carrying the gltA inactivation together with an NADP-glutamate dehydrogenase structural gene mutation (gdhA) was unable to grow on ammonium or on nitrogen sources metabolized via ammonium. The gltA gene was located to linkage group V of the A. nidulans genetic map.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Aspergillus nidulans / genetics*
  • Aspergillus nidulans / growth & development
  • Aspergillus nidulans / metabolism*
  • Base Sequence
  • Chromosome Mapping
  • Cloning, Molecular
  • DNA Primers / genetics
  • Genes, Fungal*
  • Glutamate Dehydrogenase (NADP+) / metabolism
  • Glutamate Synthase / genetics*
  • Molecular Sequence Data
  • Mutation
  • Quaternary Ammonium Compounds / metabolism*
  • Sequence Homology, Amino Acid

Substances

  • DNA Primers
  • Quaternary Ammonium Compounds
  • glutamate synthase A
  • Glutamate Synthase
  • Glutamate Dehydrogenase (NADP+)

Associated data

  • GENBANK/AF073360