State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
Department of Biology and Biological Engineering, Chalmers University of Technology, SE41296 Gothenburg, Sweden.
FEMS Yeast Res. 2018 Dec 1;18(8). doi: 10.1093/femsyr/foy091.
The Saccharomyces cerevisiae transcription factor (TF) Stb5 is known to be involved in regulating NADPH generation. We explored its role by combining DNA binding studies with transcriptome analysis at four environmental conditions that were selected to cover a range of different metabolic states. Using ChIP-exo, DNA binding targets of Stb5 were found to confirm many previously proposed binding targets, in particular genes encoding enzymes involved in NADPH generation and the pentose-phosphate (PP) pathway. Transcriptome analysis of an STB5 deletion strain revealed transcriptional changes in direct regulation targets of Stb5, including several PP pathway genes as well as additional novel regulatory targets, but interestingly not including the proposed PP pathway flux controlling enzyme Zwf1. Consistently, NADPH levels were found to decrease significantly with STB5 deletion in cultures with aerobic, glucose metabolism. We also found reduced growth for the STB5 deletion strain in similar conditions as those with reduced NADPH levels, supporting a role for Stb5 in NADPH generation through the PP pathway. We finally explored the flux distribution by genome scale modelling simulations and found a decreased flux in both NADPH generating as well as consuming reactions in the STB5 deletion strain.
酿酒酵母转录因子（TF）Stb5 已知参与调节 NADPH 的生成。我们通过将 DNA 结合研究与转录组分析相结合，探索了其在四种环境条件下的作用，这些条件的选择涵盖了不同代谢状态的范围。使用 ChIP-exo，发现 Stb5 的 DNA 结合靶标证实了许多先前提出的结合靶标，特别是编码参与 NADPH 生成和戊糖磷酸（PP）途径的酶的基因。STB5 缺失菌株的转录组分析显示，Stb5 的直接调控靶标发生了转录变化，包括几个 PP 途径基因以及其他新的调控靶标，但有趣的是，不包括拟议的 PP 途径通量控制酶 Zwf1。一致地，在有氧葡萄糖代谢的培养物中，STB5 缺失导致 NADPH 水平显著降低。我们还发现，在 NADPH 水平降低的类似条件下，STB5 缺失菌株的生长减少，这支持了 Stb5 通过 PP 途径生成 NADPH 的作用。最后，我们通过基因组规模建模模拟探索了通量分布，发现 STB5 缺失菌株中 NADPH 生成和消耗反应的通量均降低。
