The wide-domain carbon catabolite repressor CreA indirectly controls expression of the Aspergillus nidulans xlnB gene, encoding the acidic endo-beta-(1,4)-xylanase X-24
M. Orejas et al., The wide-domain carbon catabolite repressor CreA indirectly controls expression of the Aspergillus nidulans xlnB gene, encoding the acidic endo-beta-(1,4)-xylanase X-24, J BACT, 183(5), 2001, pp. 1517-1523
The Aspergillus nidulans xlnB gene, which encodes the acidic endo-beta-(1,4
)-xylanase X-24, is expressed when xylose is present as the sole carbon sou
rce and repressed in the presence of glucose. That the mutation creA(d)30 r
esults in considerably elevated levels of xlnB mRNA indicates a role for th
e wide-domain repressor CreA in the repression of xlnB promoter (xlnBp) act
ivity. Functional analyses of xlnBp::goxC reporter constructs show that non
e of the four CreA consensus target sites identified in xlnBp are functiona
l in vivo. The CreA repressor is thus likely to exert carbon catabolite rep
ression via an indirect mechanism rather than to influence xlnB expression
by acting directly on xlnB.