Abstract The regulation of transcription of the glucoamylase-encoding gene ( glaA) of Aspergillus niger was studied. To facilitate this study a reporter strain containing a fusion of the glaA promoter ( P glaA) of A. niger to the β-glucuronidase-encoding gene ( uidA) of Escherichia coli was constructed. To analyze whether regulatory proteins are involved in the regulation of glaA, multiple copies of P glaA were introduced into this reporter strain. Analysis of the resulting strains revealed that introduction of an increasing number of P glaA copies resulted in lower expression of the uidA reporter gene and the endogenous glaA gene in cultures cultivated on different inducing carbon sources. However, repression by xylose was not influenced by the copy number of P glaA . These results indicate that the expression of genes under control of P glaA are regulated by specific trans-acting regulatory protein (s). Deletion analysis of P glaA indicated that regulatory proteins interact with DNA sequences within 0.5-kb upstream from the ATG, whereas sequences between about 0.8- and 0.5-kb upstream from the ATG are required for high-level expression of glaA.