Transcriptional activator, AoXlnR, mediates cellulose‐inductive expression of the xylanolytic and cellulolytic genes in Aspergillus oryzae

Abstract

AoXlnR was isolated as a transcriptional activator of the major xylanase gene, xynF1, in Aspergillus oryzae. To investigate the spectrum of genes under the control of AoXlnR, expression of the xylanolytic and cellulolytic genes in an A. oryzae wild type strain, an AoxlnR disruptant and an AoXlnR overexpressed strain was analyzed by Northern blotting. AoXlnR mediated expression of at least four xylanolytic genes and four cellulolytic genes when induced by xylan and D-xylose. Moreover, AoXlnR was newly found to mediate the celluloseinductive expression of the xylanolytic genes as well as the cellulolytic genes. ß

ManR, a Transcriptional Regulator of the β-Mannan Utilization System, Controls the Cellulose Utilization System in <i>Aspergillus oryzae</i>

“…13) Moreover, D-cellobiose, a hydrolytic product of cellulose, causes increased expression of four cellulolytic enzyme genes (celC, celD, cbhD, and bgl5), and the high level expression of the four cellulolytic enzyme genes requires the function of XlnR 11,12,16) and ManR (this study). eglA is regulated by ManR (this study), but is not regulated by XlnR.…”

“…CreA is a well-known transcriptional repressor involved in carbon catabolite repression, that strongly suppresses cellulolytic enzyme production in Aspergillus species in the presence of glucose. [5][6][7][8] XlnR, a transcriptional regulator of xylanolytic enzyme genes, 9,10) positively regulates the expression of genes for cellulolytic enzymes in A. niger and A. oryzae, 11,12) but the regulatory mechanisms of cellulolytic enzyme genes in A. oryzae are very complex and not fully understood.…”

Effects of clbR overexpression on enzyme production in Aspergillus aculeatus vary depending on the cellulosic biomass-degrading enzyme species

“…An equal volume of culture supernatant from each strain was analyzed by two-dimensional (2D) polyacrylamide gel electrophoresis using a non-linear immobilized pH gradient (3)(4)(5)(6)(7)(8)(9)(10) in the first dimension of separation. Detected protein spots were excised from the gels, digested with trypsin, and analyzed by LCMS-IT-TOF.…”

“…3,4) Furthermore, overexpression of xlnR results in increased expression of both xylanolytic and cellulolytic genes in Aspergillus oryzae. 4) These data demonstrated that enzyme production could be improved by exploiting the function of a pathway-specific positive transcription factor.…”

“…3,4) Furthermore, overexpression of xlnR results in increased expression of both xylanolytic and cellulolytic genes in Aspergillus oryzae. 4) These data demonstrated that enzyme production could be improved by exploiting the function of a pathway-specific positive transcription factor. Although Xyr1, a XlnR homolog in T. reesei, plays a major role in all induction modes of genes encoding cellulosic biomass-degrading enzymes, it has been reported that a XlnR-independent signaling pathway exists in other species such as Aspergillus nidulans, 5) A. oryzae,…”