A binuclear zinc transcription factor binds the host isoflavonoid-responsive element in a fungal cytochrome p450 gene responsible for detoxification.
The PDA1 gene of the filamentous fungus Nectria haematococca MPVI (anamorph: Fusarium solani) encodes pisatin demethylase, a cytochrome P450. Pisatin is a fungistatic isoflavonoid produced by garden pea (Pisum sativum), a host for this fungus. Pisatin demethylase detoxifies pisatin and functions as a virulence factor for this fungus. Pisatin induces PDA1 expression both in cultured mycelia as well as during pathogenesis on pea. The regulatory element within PDA1 that provides pisatin-responsive expression was identified using a combination of in vivo functional analysis and in vitro binding analysis. The 40 bp pisatin-responsive element is located 635 bp upstream of the PDA1 transcription start site. This element was sufficient to provide strong pisatin-induced expression to a minimal promoter in vivo and was required for pisatin regulation of the PDA1 promoter. A gene encoding a DNA-binding protein specific to this 40 bp element was isolated from a N. haematococca cDNA library using the yeast one-hybrid screen. The cloned gene possesses sequence motifs found in the binuclear zinc (Cys 6-Zn 2) family of transcription factors unique to fungi. The results suggest that it is a regulator of this fungal cytochrome P450 gene and may provide pisatin-responsive regulation.
Khan
Rana
R
Molecular and Cellular Biology Program, University of Maryland, College Park, MD 20742, USA.
Tan
Reynold
R
Mariscal
Amanda Galvez
AG
Straney
David
D
D000981:Antiprotozoal Agents / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005670:Fusarium / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D010090:Oxidoreductases, O-Demethylating / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D036343:Pterocarpans / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*; D000094162:Phytoalexins
D000981:Antiprotozoal Agents; D003577:Cytochrome P-450 Enzyme System; D004247:DNA; D005656:Fungal Proteins; D010090:Oxidoreductases, O-Demethylating; D036343:Pterocarpans; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D037521:Virulence Factors; D015032:Zinc; C057976:pisatin demethylase; C003161:pisatin; D000094162:Phytoalexins