Molecular characterization of the Aspergillus nidulans fbxA encoding an F-box protein involved in xylanase induction

Author(s):Show less -

Colabardini, Ana Cristina ; Humanes, Ana Carolina ^[1] ; Gouvea, Paula Fagundes ; Savoldi, Marcela ; Goldman, Maria Helena S. ^[2] ; von Zeska Kress, Marcia Regina ; Bayram, Oezguer ^[3] ; de Castro Oliveira, Juliana Velasco ^[4] ; Gomes, Marcelo Darnario ^[1] ; Braus, Gerhard H. ^[3] ; Goldman, Gustavo Henrique ^{[4, 5]}

Affiliation

^[1] Univ Sao Paulo, Fac Med Ribeirao Preto, BR-14040903 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Pret, BR-14040903 Sao Paulo - Brazil

^[3] Univ Gottingen, Dept Mol Microbiol & Genet, Inst Microbiol & Genet, Gottingen - Germany

^[4] Lab Nacl Ciencia & Tecnol Bioetanol CTBE, BR-13083970 Sao Paulo - Brazil

^[5] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, BR-14040903 Sao Paulo - Brazil

• Document type: Journal article
• Source: Fungal Genetics and Biology; v. 49, n. 2, p. 130-140, FEB 2012.
• Web of Science Citations: 16

Abstract

The filamentous fungus Aspergillus nidulans has been used as a fungal model system to study the regulation of xylanase production. These genes are activated at transcriptional level by the master regulator the transcriptional factor XInR and repressed by carbon catabolite repression (CCR) mediated by the wide-domain repressor CreA. Here, we screened a collection of 42 A. nidulans F-box deletion mutants grown either in xylose or xylan as the single carbon source in the presence of the glucose analog 2-deoxy-D-glucose, aiming to identify mutants that have deregulated xylanase induction. We were able to recognize a null mutant in a gene (fbxA) that has decreased xylanase activity and reduced xInA and xInD mRNA accumulation. The Delta fbxA mutant interacts genetically with creAd-30, creB15, and creC27 mutants. FbxA is a novel protein containing a functional F-box domain that binds to Skp1 from the SCF-type ligase. Blastp analysis suggested that FbxA is a protein exclusive from fungi, without any apparent homologs in higher eukaryotes. Our work emphasizes the importance of the ubiquitination in the A. nidulans xylanase induction and CCR. The identification of FbxA provides another layer of complexity to xylanase induction and CCR phenomena in filamentous fungi. (C) 2011 Elsevier Inc. All rights reserved. (AU)