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

作者：Colabardini Ana Cristina; Humanes Ana Carolina; Gouvea Paula Fagundes; Savoldi Marcela; Goldman Maria Helena S; von Zeska Kress Marcia Regina; Bayram Oezguer; de Castro Oliveira Juliana Velasco; Gomes Marcelo Darnario; Braus Gerhard H; Goldman Gustavo Henrique^*

来源：Fungal Genetics and Biology, 2012, 49(2): 130-140.

DOI：10.1016/j.fgb.2011.11.004

• Aspergillus nidulans
• Xylanase
• Catabolite repression
• CreA
• XInR
• F-box proteins
• Xylanase

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.

• 出版日期2012-2