An Aspergillus oryzae CCAAT-binding protein, AoCP, is involved in the high-level expression of the Taka-amylase A gene

Abstract

Aspergillus oryzae contains a nuclear protein designated AoCP, which binds specifically to a CCAAT sequence in the promoter region of the A. oryzae Taka-amylase A gene. A gene encoding a homologue of Aspergillus nidulans HAPC, a subunit of the A. nidulans CCAAT binding complex, was isolated from A. oryzae and designated AohapC. AoHAPC comprises 215 amino acids and shows 84% identity to A. nidulans HAPC. Transformation of the A. nidulans hapC deletion strain with the AohapC gene restored the CCAAT binding activity, resulting in both enhancement of taa gene expression and complementation for the poor growth phenotype of this strain. Furthermore, introduction of the AohapC gene also restored the expression of the A. nidulans eglA gene, encoding an endo-β-1,4-glucanase, in the deletion strain. These results indicate functional interchangeability of the genes from two species.