The yeast his3 gene encodes the imidazole glycerolphosphate dehydratase (E.C.18.104.22.168) of the histidine biosynthetic pathway. We isolated the his3 homologue of Aspergillus nidulans, named hisB, respectively. Sequence analysis revealed an open reading frame of 801 kb, interrupted by an intron of 58 kb. The cDNA clone complements the histidine biosynthetic defect of the yeast his3 mutant, which indicates functional equivalence of these homologs. Further evidence derived from sequence similarities which range between 54 and 38 % identities to other imidazole glycerolphosphate dehydratases. A transcriptional regulation of hisB by histidine itself does not occur. The yeast his3 gene is regulated by the mechanism of general amino acid control. We showed that the hisB gene in Aspergillus nidulans is transcriptionally activated after amino acid starvation. Two putative binding sites for the transcription factor CpcA of the general control pathway of Aspergillus nidulans could be identified 379 and 228 by upstream of the translational start point.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)