%0 Journal Article
%T Establishment of the Inducible Tet-On System for the Activation of the Silent Trichosetin Gene Cluster in Fusarium fujikuroi
%A Bettina Tudzynski
%A Birgit Arndt
%A Hans-Ulrich Humpf
%A Leonie Baumann
%A Lisa Helene Apken
%A Lucas Maciel Mauriz Marques
%A Slavica Janevska
%J Archive of "Toxins".
%D 2017
%R 10.3390/toxins9040126
%X The PKS-NRPS-derived tetramic acid equisetin and its N-desmethyl derivative trichosetin exhibit remarkable biological activities against a variety of organisms, including plants and bacteria, e.g., Staphylococcus aureus. The equisetin biosynthetic gene cluster was first described in Fusarium heterosporum, a species distantly related to the notorious rice pathogen Fusarium fujikuroi. Here we present the activation and characterization of a homologous, but silent, gene cluster in F. fujikuroi. Bioinformatic analysis revealed that this cluster does not contain the equisetin N-methyltransferase gene eqxD and consequently, trichosetin was isolated as final product. The adaption of the inducible, tetracycline-dependent Tet-on promoter system from Aspergillus niger achieved a controlled overproduction of this toxic metabolite and a functional characterization of each cluster gene in F. fujikuroi. Overexpression of one of the two cluster-specific transcription factor (TF) genes, TF22, led to an activation of the three biosynthetic cluster genes, including the PKS-NRPS key gene. In contrast, overexpression of TF23, encoding a second Zn(II)2Cys6 TF, did not activate adjacent cluster genes. Instead, TF23 was induced by the final product trichosetin and was required for expression of the transporter-encoding gene MFS-T. TF23 and MFS-T likely act in consort and contribute to detoxification of trichosetin and therefore, self-protection of the producing fungus
%K Fungi
%K Fusarium fujikuroi
%K secondary metabolism
%K PKS-NRPS
%K biosynthesis
%K gene regulation
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5408200/