Multiple Forms of Arginase Are Differentially Expressed from a Single Locus in Neurospora crassa

• Published in: The Journal of biological chemistry Vol. 273; no. 45; pp. 29776 - 29785
• Main Authors: Marathe, Sudhir, Yu, Yeon Gyu, Turner, Gloria E., Palmier, Christine, Weiss, Richard L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 06.11.1998; American Society for Biochemistry and Molecular Biology
• Subjects: AGA LOCUS; Amino Acid Sequence; AMINO ACID SEQUENCES; Animals; ARGINASA; ARGINASE; Arginase - genetics; ARN MENSAJERO; ARN MESSAGER; Base Sequence; CARTE GENETIQUE; CHEMICAL COMPOSITION; CHROMOSOME MAPS; Cloning, Molecular; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; DNA, Recombinant; EXPRESION GENICA; EXPRESSION DES GENES; GENBANK/L20687; GENE; GENE EXPRESSION; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Fungal; GENES; GENETIC MAPPING; GENETIC MAPS; GENETIC MARKERS; Humans; ISOENZIMAS; ISOENZYME; ISOENZYMES; LOCI; LOCUS; MAPAS GENETICOS; MARCADORES GENETICOS; MARQUEUR GENETIQUE; MESSENGER RNA; MOLECULAR SEQUENCE DATA; MOLECULAR WEIGHT; MUTACION; Mutagenesis, Site-Directed; MUTATION; NEUROSPORA CRASSA; Neurospora crassa - enzymology; Neurospora crassa - genetics; NUCLEOTIDE SEQUENCE; OPEN READING FRAMES; PESO MOLECULAR; POIDS MOLECULAIRE; Polymorphism, Restriction Fragment Length; RFLP; SECUENCIA NUCLEOTIDICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; STRUCTURAL GENES; TARGETED MUTAGENESIS
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.45.29776

The Neurospora crassa catabolic enzyme, arginase (l-arginine amidinohydrolase, EC 3.5.3.1), exists in multiple forms. Multiple forms of arginase are found in many vertebrates, but this is the only reported example in a microbial organism. The two major forms are structurally similar with subunit sizes of 36 and 41 kDa, respectively. The larger form is produced by mycelia growing in arginine-supplemented medium. Both forms are localized in the cytosol. The structural gene for arginase,aga, has been cloned and sequenced; it contains a 358-codon open reading frame with three in-frame ATGs at the amino terminus. Mutagenesis of these ATGs revealed that the first ATG initiates the 41-kDa protein and the third ATG initiates the 36-kDa protein. Mutation of the second ATG has no effect on translation. Northern analysis demonstrated that a 1.4-kilobase (kb) transcript is synthesized in minimal medium and both a 1.4- and 1.7-kb transcript are produced in arginine-supplemented medium. Primer extension identified the 5′ ends of each transcript and demonstrated that the first and third ATG of the open reading frame are the initial AUGs of the 1.7- and 1.4-kb mRNA, respectively. The results suggest that a basal promoter produces the 1.4-kb transcript and an arginine “activated” promoter is responsible for the 1.7-kb transcript. Tandem promoters are rare in eukaryotic organisms, and they often regulate developmental or tissue-specific gene expression. The possibility that arginase has a role in differentiation in N. crassa is being investigated.