AreB, the nitrogen and carbon regulator in Aspergillus nidulans

Nitrogen and carbon repression general regulatory systems modulate the expression of target genes participating in utilization of alternative nitrogen/carbon sources, resulting in transcription only when preferred sources are limiting. In Aspergillus nidulans, the GATA transcription factor AreB was identified as nitrogen regulator whose activity depends on both nitrogen and carbon source (Conlon et al., 2001; Macios et al., 2012; Chudzicka - Ormanec et al., 2019). In this work, we performed a transcriptomic analysis of areB deletion and the wild type strains grown under different carbon/nitrogen conditions and showed that AreB participates both in nitrogen and carbon regulation. Observed positive and negative effects of areB deletion are at least partially, indirect as the expression of some transcription factor coding genes is changed in areB deletion strain. Overall design: Comparative gene expression profiling analysis of RNA-seq data for areB? and the control areB+ (wild type) strains, grown under carbon repressing (1% glucose) or non-repressing (0.1% fructose); and under nitrogen repressing (10 mM ammonium tartrate) or non-repressing (5mM urea) conditions in three biological replicates.

氮代谢阻遏与碳代谢阻遏的通用调控系统可调控参与替代氮源/碳源利用的靶基因表达，仅在偏好性底物匮乏时才启动靶基因的转录。在构巢曲霉（Aspergillus nidulans）中，GATA转录因子（GATA transcription factor）AreB被鉴定为氮源调控因子，其活性同时依赖于氮源与碳源状态（Conlon等，2001；Macios等，2012；Chudzicka-Ormanec等，2019）。本研究对不同碳/氮条件下培养的areB?与野生型菌株开展转录组分析，结果证实AreB同时参与氮源与碳源调控。本研究观察到areB缺失所产生的正向与负向调控效应至少部分为间接效应，原因是areB缺失菌株中部分转录因子编码基因的表达发生了改变。实验整体设计：对areB?与对照areB+（野生型）菌株的RNA测序（RNA-seq）数据开展比较基因表达谱分析；菌株分别在碳阻遏（1%葡萄糖）或非碳阻遏（0.1%果糖）条件下培养，同时分别在氮阻遏（10 mM酒石酸铵）或非氮阻遏（5 mM尿素）条件下培养，每组均设置3次生物学重复。