title: PrnA, a Zn2Cys6 activator with a unique DNA recognition mode, requires inducer for in vivo binding.
abstract: The PrnA transcriptional activator of Aspergillus nidulans binds as a dimer to CCGG-N-CCGG inverted repeats and to CCGG-6/7N-CCGG direct repeats. The binding specificity of the PrnA Zn cluster differs from that of the Gal4p/Ppr1p/UaY/Put3p group of proteins. Chimeras with UaY, a protein that strictly recognizes a CGG-6N-CCG motif, show that the recognition of the direct repeats necessitates the PrnA dimerization and linker elements, but the recognition of the CCGG-N-CCGG inverted repeats depends crucially on the PrnA Zn binuclear cluster and/or on residues amino-terminal to it. Three high-affinity sites in two different promoters have been visualized by in vivo methylation protection. Proline induction is essential for in vivo binding to these three sites but, as shown previously, not for nuclear entry. Simultaneous repression by ammonium and glucose does not affect in vivo binding to these high-affinity sites. PrnA differs from the isofunctional Saccharomyces cerevisiae protein Put3p, both in its unique binding specificity and in the requirement of induction for in vivo DNA binding.
authors.affiliation: Institut de Génétique et Microbiologie, Université Paris-Sud, Bâtiment 409, UMR 8621 CNRS, 91405 Orsay Cedex, France.
authors.forename: Dennis
authors.initials: D
authors.lastname: Gómez
authors.forename: Beatriz
authors.initials: B
authors.lastname: Cubero
authors.forename: Gianna
authors.initials: G
authors.lastname: Cecchetto
authors.forename: Claudio
authors.initials: C
authors.lastname: Scazzocchio
mesh_terms: D001234:Aspergillus niger / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D003545:Cysteine; D018983:DNA Footprinting; D019175:DNA Methylation; D004271:DNA, Fungal / Q000378:metabolism*; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; C113261:PrnA protein, Aspergillus nidulans; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D015032:Zinc; D003545:Cysteine