CLONING AND EXPRESSION OF CDNA-ENCODING A PROTEIN THAT BINDS A PALINDROMIC PROMOTER ELEMENT ESSENTIAL FOR INDUCTION OF FUNGAL CUTINASE BY PLANT CUTIN

Previous studies showed that a palindromic sequence located at -159 base pairs is essential for induction of cutinase gene in Fusarium solani f. sp. pisi (Nectria haematococca mating type VI) by the hydroxy fatty acids from plant cutin and that a 50-kDa nuclear protein binds to a promoter that contains this element. Screening of a phage lambda gt11 expression library with the concatenated palindromic sequence as the probe identified a cDNA encoding a palindrome-binding protein (PBP). Nucleotide sequence of this cDNA revealed an open reading frame that would code for PBP with a calculated molecular weight of 49,847. This PBP contains a putative nuclear localization signal and a zinc finger motif sharing homology with the zinc finger DNA binding domains of transcription factors from mammals, Saccharomyces cerevisiae, Neurospora crassa, and Ustilago maydis. A highly basic region immediately adjacent to the carboxyl side of the zinc finger was also observed. PBP expressed in Escherichia coli showed specific binding to the palindromic DNA fragment.