Cloning and expression analysis of the ornithine decarboxylase gene (PbrODC) of the pathogenic fungus Paracoccidioides brasiliensis

• Published in: Yeast (Chichester, England) England), 2004-02, Vol.21 (3), p.211-218
• Main Authors: Niño‐Vega, Gustavo A., Sorais, Françoise, Calcagno, Ana‐María, Ruiz‐Herrera, José, Martínez‐Espinoza, Alfredo D., San‐Blas, Gioconda
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Base Sequence; Blotting, Northern; Cloning, Molecular; dimorphic transition; DNA, Fungal - chemistry; DNA, Fungal - genetics; gene expression; Gene Expression Regulation, Fungal; Gene Library; Isoelectric Point; Molecular Sequence Data; Molecular Weight; Onygenales; Ornithine Decarboxylase - genetics; Paracoccidioides - enzymology; Paracoccidioides - genetics; Paracoccidioides - growth & development; Paracoccidioides brasiliensis; Phylogeny; polyamines; Polymerase Chain Reaction; RNA, Fungal - chemistry; RNA, Fungal - genetics; Sequence Analysis, DNA; taxonomy; Transformation, Genetic
• ISSN: 0749-503X; 1097-0061
• DOI: 10.1002/yea.1066

We describe the isolation and sequencing of PbrODC, the gene encoding ornithine decarboxylase (ODC) in Paracoccidioides brasiliensis. The gene contains a single open reading frame made of 1413 bp with a single intron (72 bp), and encodes a 447 amino acid polypeptide with a predicted molecular weight of 50.0 kDa, an isoelectric point of 4.9 and a high similarity to other fungal ornithine decarboxylases. Functionality of the gene was demonstrated by transformation into a Saccharomyces cerevisiae odc null mutant. A phylogenetic tree generated with several fungal ODCs provided additional evidence to favour a taxonomic position for P. brasiliensis as an ascomycetous fungus, belonging to the order Onygenales. Expression of the PbrODC gene was determined by Northern analyses during growth of the mycelial and yeast forms, and through the temperature‐regulated dimorphic transition between these two extreme phases. Expression of PbrODC remained constant at all stages of the fungal growth, and did not correlate with a previously observed increase in the activity of ornithine decarboxylase at the onset of the budding process in both yeast growth and mycelium‐to‐yeast transition. Accordingly, post‐transcriptional regulation for the product of PbrODC is suggested. The PbrODC gene sequence is available at the GenBank database under Accession No. AF212867. Copyright © 2004 John Wiley & Sons, Ltd.