Nucleotide sequence and expression of the gene encoding NADP(+) dependent glutamate dehydrogenase (gdhA) from Agaricus bisporus

The gene encoding NADP(+)-dependent glutamate dehydrogenase (gdhA) was isolated from an Agaricus bisporus recombinant phage lambda library. The deduced amino acid sequence would specify a 457-amino acid protein that is highly homologous in sequence to those derived from previously isolated and characterized genes coding for microbial NADP(+)-GDH. The open reading frame is interrupted by six introns. None of the introns is located at either one of the positions of the two introns conserved in the corresponding open reading frames of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. Northern analysis suggests that the A. bisporus gdhA gene is transcriptionally regulated and that, unlike the case in ascomycetes, transcription of this gene is repressed upon the addition of ammonium to the culture.