Die Rolle zweier Zn(II)2Cys6 binukleärer Clusterproteine in der sexuellen Entwicklung von Aspergillus nidulans

The homothallic ascomycete Aspergillus nidulans reproduces asexually through conidiospores and sexually through ascospores, formed in cleistothecia. Development of cleistothecia is strongly regulated and happens only, if several biotic and abiotic factors play together. For example, sexual development needs an air interface and darkness to be started, whereas asexual structures are formed in the light. The molecular regulation of sexual development is largely unknown, especially after the onset of the developmental program. The availability of the genomic DNA sequence of A. nidulans allowed us to apply a reverse genetic approach and ask whether regulators discovered in other organisms exist in A. nidulans and what there function would be. Recently, a Zn(II)2Cys6 transcription factor (Pro1) was described in the homothallic fungus Sordaria macrospora (Masloff et al., 1999). Mutation of this regulator resulted in a specific block of perithecium development and thus no mature fruiting bodies are formed. Low stringency hybridisation experiments using the pro1 gene as a probe suggested that a homologue might exist in A. nidulans. Therefore, we have screened the genomic DNA database of A. nidulans and identified two genes whose translation products shared sequence similarities to Pro1. We analysed the function of these Zn(II)2Cys6 transcription factors.