Improving heterologous gene expression in Aspergillus niger by introducing multiple copies of protein-binding sequence containing CCAAT to the promoter

Aims: To increase the expression level of heterologous gene in Aspergillus niger. Methods and Results: Inserting multiple copies of an activator protein-binding site originally encoded in the cis-regulatory region of A. niger glucoamylase gene (glaA), CCAAT-containing sequence, into the promoter of an expression plasmid greatly enhanced the production of heterologous protein. Conclusion: The promoter activity was increased by the introduction of the CCAAT-containing sequence resulting in increased gene expression. Significance and Impact of the Study: This study provides evidence that the CCAAT-containing region of the glaA promoter of A. niger is a binding site for a positive transcriptional factor and demonstrates the possibility for improving the expression of both heterologous and endogenous genes in Aspergillus.