Characterization of the amyR gene encoding a transcriptional activator forthe amylase genes in Aspergillus nidulans

Citation
S. Tani et al., Characterization of the amyR gene encoding a transcriptional activator forthe amylase genes in Aspergillus nidulans, CURR GENET, 39(1), 2001, pp. 10-15
Citations number
24
Categorie Soggetti
Molecular Biology & Genetics
Journal title
CURRENT GENETICS
ISSN journal
01728083 → ACNP
Volume
39
Issue
1
Year of publication
2001
Pages
10 - 15
Database
ISI
SICI code
0172-8083(200102)39:1<10:COTAGE>2.0.ZU;2-R
Abstract
The Aspergillus nidulans amyR gene and its cDNA were cloned and sequenced. The genomic gene comprised 2,092 bp, interrupted by two short introns, and encoded a cys-6 zinc transcriptional activator (AMYR) of 662 amino acid res idues with a calculated molecular mass of 72,862 Da. Disruption of the amyR gene caused defects in the utilization of maltose and starch and abolished expression of the taaG2 gene encoding A. oryzae Taka-amylase A, which is i nducibly and abundantly expressed in the wild-type A. nidulans. Expression of the amyR gene was under the control of the carbon catabolite repressor, CREA. The growth defect of the malA1 mutant on maltose was complemented by the amyR gene; and the amyR gene derived from the mutant possessed a single mutation, from A to T, at position 1,483, resulting in a substitution of H is478 to Leu. These results indicate that the amyR gene is identical to the genetically defined malA gene. AMYR possessed five domains (Zn and MH1-MH4 ) homologous to Mal63p, a transcriptional activator for the genes involved in maltose utilization in Saccharomyces cerevisiae. The His478 to Leu subst itution lay within the MH3 domain, corresponding to the negative regulatory domain of Mal63p which relieves the inhibitory effect on the activation fu nction in response to maltose.