Induced expression of the Aspergillus nidulans QUTE gene introduced by transformation into Neurospora crassa

The qa-2 gene of Neurospora crassa encodes catabolic dehydroquinase which catabolizes dehydroquinic acid to dehydroshikimic acid. The QUTE gene of Aspergillus nidulans corresponds to the qa-2 gene of N. crassa. The plasmid pEH1 containing the QUTE gene from A. nidulans was used to transform a qa-2- strain of N. crassa. In Southern blot analyses, DNAs isolated from these transformants hybridized specifically to the QUTE gene probe. Northern blot analyses indicated that QUTE mRNA was produced in the transformants. The functional integrity of the QUTE gene in N. crassa was indicated by transformants which had regained the ability to grow on quinic acid as sole carbon source. Enzyme assays indicated that the specific activities of catabolic dehydroquinase induced by quinic acid in the transformants ranged from 4% to 32% of that induced in wild-type N. crassa. The evidence that the QUTE structural gene of A. nidulans is inducible when introduced into the N. crassa genome implies that the N. crassa qa activator protein can recognize, at least to a limited extent, DNA binding sequences 5' to the QUTE gene.