[Regulation of gene expression in Aspergilli]

Area of Science:

• Molecular Biology
• Gene Regulation
• Aspergillus Research

Background:

• The Aspergillus oryzae Taka-amylase A (TAA) gene serves as a model for studying gene expression regulation in Aspergilli.
• The TAA gene promoter contains a TATA box and CCAAT sequence, crucial for gene regulation.

Purpose of the Study:

• To investigate the regulatory mechanisms of the TAA gene promoter in Aspergillus.
• To identify and characterize the nuclear protein (AnCP) that binds to the CCAAT sequence.

Main Methods:

• Site-directed mutagenesis of the TAA promoter's CCAAT sequence.
• Nuclear protein binding assays.
• Isolation and expression of the Aspergillus nidulans hapC gene.
• Production of anti-HapC antiserum.

Main Results:

• Replacement of the CCAAT sequence abolished AnCP binding and inhibited promoter activity.
• The Aspergillus nidulans HapC protein functions as a subunit of the AnCP complex.
• AnCP is identified as the fungal counterpart to the yeast Hap complex.

Conclusions:

• The CCAAT sequence and its binding protein AnCP are essential for TAA gene promoter activity.
• The Aspergillus HapC protein is a functional component of AnCP, analogous to yeast HAP complex subunits.
• This study elucidates a conserved mechanism of eukaryotic gene regulation across different fungal species.