Trichoderma reesei XYR1 recruits SWI/SNF to facilitate cellulase gene expression
Trichoderma reesei XYR1 recruits SWI/SNF to facilitate cellulase gene expression
复制标题
里氏木霉 XYR1 招募 SWI/SNF 促进纤维素酶基因表达
DOI：
10.1111/mmi.14352
复制
发表时间：
2019-07-25
影响因子：
3.6
通讯作者：
Liu, Weifeng
中科院分区：
文献类型：
--
作者：
Cao, Yanli;Zheng, Fanglin;Liu, Weifeng
里氏木霉纤维素酶基因的表达对环境信号高度敏感，受到多种转录因子的严格调控。XYR1（木聚糖酶调节因子1）已被确定为纤维素酶/半纤维素酶基因表达的最重要的转录激活因子，尽管其确切的反激活机制在很大程度上尚不清楚。在这里，我们发现XYR1的激活域与SWI/SNF复合物的TrSNF12亚基的T. reesei同源物相互作用。Trsnf12的缺失明显损害了诱导的纤维素酶基因的表达。其他SWI/SNF亚基（包括催化亚基）的个体缺失也严重损害了纤维素酶基因的表达，并干扰了纤维素诱导时cbh1和eg1启动子中组蛋白H4的缺失。此外，我们发现SWI/SNF占据纤维素酶基因启动子严格要求XYR1和TrSNF12，而XYR1与这些启动子结合时TrSNF12是不需要的。这些数据表明，XYR1通过与TrSNF12的直接相互作用来募集SWI/SNF，从而在纤维素酶基因启动子处重塑染色质，从而激活纤维素酶基因表达，从而启动T. reesei的纤维素分解反应。
Cellulase gene expression in Trichoderma reesei is highly responsive to environmental cues and is under stringent regulation by multiple transcription factors. XYR1 (Xylanase regulator 1) has been identified as the most important transcriptional activator of cellulase/hemicellulase gene expression although the precise transactivating mechanism remains largely elusive. Here we show that the activation domain of XYR1 interacts with the T. reesei homolog of the TrSNF12 subunit of SWI/SNF complex. Deletion of Trsnf12 markedly impaired the induced cellulase gene expression. Individual loss of other SWI/SNF subunits including the catalytic subunit also severely compromised cellulase gene expression and interfered with loss of histone H4 in the cbh1 and eg1 promoters upon cellulose induction. In addition, we find that the SWI/SNF occupancy on cellulase gene promoters strictly required XYR1 and TrSNF12 but TrSNF12 was dispensable for the XYR1 binding to these promoters. These data suggest a model in which XYR1 recruits SWI/SNF through direct interactions with TrSNF12 to remodel chromatin at cellulase gene promoters, thereby activating cellulase gene expression to initiate the cellulolytic response in T. reesei.