Genes regulated by AoXlnR, the xylanolytic and cellulolytic transcriptional regulator, in Aspergillus oryzae
Genes regulated by AoXlnR, the xylanolytic and cellulolytic transcriptional regulator, in Aspergillus oryzae
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DOI：
10.1007/s00253-009-2236-9
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发表时间：
2009-11-01
影响因子：
5
通讯作者：
Kobayashi, Tetsuo
中科院分区：
文献类型：
--
作者：
Noguchi, Yuji;Sano, Motoaki;Kobayashi, Tetsuo
XlnR是曲霉属中木聚糖分解和纤维素分解基因的Zn（II）（2）Cys（6）转录激活因子。aoxlnR基因在曲霉Aspergilluscaugus（A.表达产物经双向电泳鉴定，表达产物中有近40种分泌蛋白。鉴定AoXlnR转录靶的DNA微阵列分析导致鉴定出75个基因，其在AoXlnR过度生产者中的表达比在破坏者中的表达增加超过5倍。其中，预测有32个基因编码糖苷水解酶，突出了AoXlnR在生物质降解中的生物技术重要性。这75个基因包括先前鉴定为AoXlnR靶标的基因（xynF 1、xynF 3、xynG 2、xylA、celA、celB、celC和celD）。预测36个基因是胞外的，这与分泌的蛋白质的数量一致，并且61个基因在其启动子区中具有推定的XlnR结合位点（5 '-GGCTAA-3'、5 '-GGCTAG-3'和5 '-GGCTGA-3'）。基因的功能注释显示，AoXlnR调节水解基因的表达，用于降解β-1，4-木聚糖、阿拉伯木聚糖、纤维素和木葡聚糖，以及调节分解代谢基因的表达，用于将d-木糖转化为木酮糖-5-磷酸。此外，编码葡萄糖-6-磷酸1-脱氢酶和l-阿拉伯糖醇-4-脱氢酶的基因参与了d-葡萄糖和l-阿拉伯糖催化酶，也似乎是AoXlnR的靶点。
XlnR is a Zn(II)(2)Cys(6) transcriptional activator of xylanolytic and cellulolytic genes in Aspergillus. Overexpression of the aoxlnR gene in Aspergillus oryzae (A. oryzae xlnR gene) resulted in elevated xylanolytic and cellulolytic activities in the culture supernatant, in which nearly 40 secreted proteins were detected by two-dimensional electrophoresis. DNA microarray analysis to identify the transcriptional targets of AoXlnR led to the identification of 75 genes that showed more than fivefold increase in their expression in the AoXlnR overproducer than in the disruptant. Of these, 32 genes were predicted to encode a glycoside hydrolase, highlighting the biotechnological importance of AoXlnR in biomass degradation. The 75 genes included the genes previously identified as AoXlnR targets (xynF1, xynF3, xynG2, xylA, celA, celB, celC, and celD). Thirty-six genes were predicted to be extracellular, which was consistent with the number of proteins secreted, and 61 genes possessed putative XlnR-binding sites (5'-GGCTAA-3', 5'-GGCTAG-3', and 5'-GGCTGA-3') in their promoter regions. Functional annotation of the genes revealed that AoXlnR regulated the expression of hydrolytic genes for degradation of beta-1,4-xylan, arabinoxylan, cellulose, and xyloglucan and of catabolic genes for the conversion of d-xylose to xylulose-5-phosphate. In addition, genes encoding glucose-6-phosphate 1-dehydrogenase and l-arabinitol-4-dehydrogenase involved in d-glucose and l-arabinose catabolism also appeared to be targets of AoXlnR.