title: cys-3, the positive-acting sulfur regulatory gene of Neurospora crassa, encodes a protein with a putative leucine zipper DNA-binding element.
abstract: The sulfur-regulatory circuit of Neurospora crassa consists of a set of unlinked structural genes which encode sulfur-catabolic enzymes and two major regulatory genes which govern their expression. The positive-acting cys-3 regulatory gene is required to turn on the expression of the sulfur-related enzymes, whereas the other regulatory gene, scon, acts in a negative fashion to repress the synthesis of the same set of enzymes. Expression of the cys-3 regulatory gene was found to be controlled by scon and by sulfur availability. The nucleotide sequence of the cys-3 gene was determined and can be translated to yield a protein of molecular weight 25,892 which displays significant homology with the oncogene protein Fos, yeast GCN4 protein, and sea urchin histone H1. Moreover, the putative cys-3 protein has a well-defined leucine zipper element plus an adjacent charged region which together may make up a DNA-binding site. A cys-3 mutant and a cys-3 temperature-sensitive mutant lead to substitutions of glutamine for basic amino acids within the charged region and thus may alter DNA-binding properties of the cys-3 protein.
authors.affiliation: Department of Biochemistry, Ohio State University, Columbus 43210.
authors.forename: Y H
authors.initials: YH
authors.lastname: Fu
authors.forename: J V
authors.initials: JV
authors.lastname: Paietta
authors.forename: D G
authors.initials: DG
authors.lastname: Mannix
authors.forename: G A
authors.initials: GA
authors.lastname: Marzluf
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D005809:Genes, Regulator; D007930:Leucine / Q000378:metabolism; D008969:Molecular Sequence Data; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis; D013455:Sulfur / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D013455:Sulfur; D007930:Leucine