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
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.