Initiator constitutive mutation with an 'up-promoter' effect in Aspergillus nidulans.

A mutation leading to strong constitutivity for a uric acid-xanthine permease in the lower eukaryote Aspergillus nidulans has been found to be tightly linked to the putative structural gene whose expression it controls in the cis configuration. In addition, it increases the maximal induced level of transport 2.5-fold. This is the first demonstration of an initiator or promoter mutation in an eukaryote.