A. nidulans is a highly important model organism to study the secondary metabolite production. This filamentous fungus has the capacity to produce a large number of secondary metabolites, which hold great importance in human applications such as the antibiotic penicillin. On the other hand some of these metabolites can be dangerous like the aflatoxin precursor sterigmatocystin. Hülle cells are a unique cell type of A. nidulans and are developed during the sexual development. Unfortunately, very few amount of information is available. In a previous experiment, it was shown that proteins involved in SMs production are found in Hülle cells. According to the result, three different polyketide synthases and one uncharacterized protein with the putative function of NRPS-like were chosen, which will be analyzed in more detail in this master’s thesis.