Yu Pengju, Zhou Mi, Yu Deshui, Zhang Zhongchi, Ye Shuting, Yu Yifa, Sun Xianyun, Li Shaojie, Hu Chengcheng
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100101 China.
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 China; National Institute for Radiological Protection, China CDC, Beijing 100101 China.
J Adv Res. 2025 Jan 30. doi: 10.1016/j.jare.2025.01.046.
The synthesis and regulation of ergosterol are vital for fungal growth and stress adaptation. While ergosterol-mediated feedback regulation is a recognized mechanism controlling sterol biosynthesis in fungi, prior research suggests the presence of additional regulatory mechanisms. However, the specifics of the alternative regulatory mechanisms have not been systematically investigated.
We proposed that a regulatory network is likely to discern disturbances in sterol biosynthesis and trigger responses accordingly. This study aimed to validate the hypothesis and investigate the regulatory mechanisms.
Quantitative Real-time PCR and HPLC-MS/MS were used to explore and compare the regulation of sterol biosynthesis in different fungi. Key transcription factors involved in the alternative regulatory mechanism in Neurospora crassa were identified by phenotypic profiling of a transcription factor mutant library. ChIP-qPCR, fluorescence confocal imaging, RNA sequencing, and gene set enrichment analysis (GSEA) were used to reveal the mechanism of each transcription factor.
Unlike the canonical ergosterol-mediated feedback regulation in fungi like C. neoformans, our study demonstrated that the inhibitions of ergosterol biosynthesis at specific steps triggered distinct transcriptional responses of erg genes in fungi, including N. crassa and Aspergillus fumigatus. In N. crassa, the responses were orchestrated by different transcription factors. Specifically, the inhibition of ERG24 and ERG2 activated transcription factors SAH-2 and AtrR, resulting in the upregulation of erg24, erg2, erg25, and erg3. Furthermore, the inhibition of ERG11/CYP51 activated transcription factor NcSR, leading to the upregulation of erg11 and erg6. Phenotypic profiles of mutants of various N. crassa erg genes and the aforementioned transcription factors implied that the targeted regulation of ergosterol biosynthesis could fortify fungal viability within complex habitats.
Our study reveals a novel regulatory mechanism in fungi: targeted upregulation of specific sterol biosynthesis genes in response to given perturbations in ergosterol biosynthesis, exhibiting a higher degree of precision and sophistication in sterol biosynthesis regulation.
麦角固醇的合成与调控对真菌生长和应激适应至关重要。虽然麦角固醇介导的反馈调控是控制真菌中甾醇生物合成的公认机制，但先前的研究表明还存在其他调控机制。然而，这些替代调控机制的具体细节尚未得到系统研究。
我们提出一个调控网络可能识别甾醇生物合成中的干扰并相应地触发反应。本研究旨在验证这一假设并探究调控机制。
采用定量实时PCR和HPLC-MS/MS来探索和比较不同真菌中甾醇生物合成的调控。通过对粗糙脉孢菌转录因子突变体文库进行表型分析，鉴定参与替代调控机制的关键转录因子。采用染色质免疫沉淀定量PCR（ChIP-qPCR）、荧光共聚焦成像、RNA测序和基因集富集分析（GSEA）来揭示每个转录因子的作用机制。
与新生隐球菌等真菌中经典的麦角固醇介导的反馈调控不同，我们的研究表明，在特定步骤抑制麦角固醇生物合成会引发真菌中erg基因的不同转录反应，包括粗糙脉孢菌和烟曲霉。在粗糙脉孢菌中，这些反应由不同的转录因子协调。具体而言，抑制ERG24和ERG2会激活转录因子SAH-2和AtrR，导致erg24、erg2、erg25和erg3上调。此外，抑制ERG11/CYP51会激活转录因子NcSR，导致erg11和erg6上调。各种粗糙脉孢菌erg基因和上述转录因子突变体的表型分析表明，麦角固醇生物合成的靶向调控可增强真菌在复杂生境中的生存能力。
我们的研究揭示了真菌中的一种新调控机制：响应麦角固醇生物合成中的特定扰动，特定甾醇生物合成基因的靶向上调，在甾醇生物合成调控中表现出更高的精确性和复杂性。
