Regulatory region of the Aspergillus nidulans argB gene.

We have constructed a series of deletion plasmids which contain the Aspergillus nidulans argB gene for ornithine carbamoyltransferase (OTC). These deletions comprise the 5' upstream sequence of the argB gene. The pro- arg- strain of A. nidulans was transformed with the above plasmids. Several arg+ transformants of integration types I and II, obtained using each of the deletion plasmids, were studied, and their ability to de-repress OTC level by proline starvation was compared. It was concluded that nucleotides located between -150 and -50 bp upstream of the argB gene are significant for its cross-pathway regulation. This regulatory region contains three copies of the TGACTC hexanucleotide which is a cis-acting regulatory sequence of general amino acid control in yeast.