Expression Profile of Amylolytic Genes in Aspergillus nidulans
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<I>Aspergillus nidulans</I> possessed 16 putative amylolytic genes consisting of 7 α-glucosidase (<I>agdA-F</I>), 7 α-amylase (<I>amyA-F</I>), and 2 glucoamylase (<I>glaA</I> and <I>B</I>) genes on the genome. Among them, the <I>agdA</I>, <I>agdB</I>, <I>agdE</I>, <I>agdF</I>, <I>amyA</I>, <I>amyB</I>, <I>amyF</I>, and <I>glaB</I> genes were induced by isomaltose. AmyR, a Zn(II)<SUB>2</SUB>Cys<SUB>6</SUB> transcription factor, was required for the induction. The isomaltose-inducible genes possessed at least one consensus sequence for AmyR binding, 5′-CGGN<SUB>8</SUB>CGG, on each promoter region. None of the amylolytic genes was induced by maltose.<BR>The mRNA levels of the amylolytic genes except for <I>agdC</I>, <I>amyD</I>, and <I>amyG</I> increased under carbon-starved conditions. Release from CreA-dependent carbon catabolite repression was the main cause of the increase, but, the mRNA levels of <I>agdB</I>, <I>agdF</I>, <I>amyB</I>, <I>amyF</I>, and <I>gla</I>B increased to some extent even in a <I>creA</I> mutant. Therefore, both CreA-dependent and -independent mechanisms are involved in the up-regulation of the amylolytic genes under carbon-starved conditions.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(10), 2363-2370, 2006-10-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry