CONTROLS OF THE EXPRESSION OF ASPA, THE ASPARTYL PROTEASE GENE FROM PENICILLIUM-ROQUEFORTI

The gene (aspA) encoding the extracellular aspartyl protease from Peni cillium roqueforti was cloned and characterized. Northern hybridizatio n analyses and beta-casein degradation assays revealed that aspA was s trongly induced by casein in the medium and efficiently repressed by a mmonia. External alkaline pH overrides casein induction, resulting in aspA repression. Cis-acting motifs known to mediate nitrogen and pH re gulation of fungal gene expression are present in the aspA promoter an d protein-DNA binding experiments showed that mycelial proteins intera ct with various regions of the promoter. Due to the efficient environm ental controls on aspA expression, the promoter of aspA is an attracti ve candidate for the development of a controllable gene expression sys tem in P. roqueforti.