Reconstruction of a Global Transcriptional Regulatory Network for Control of Lipid Metabolism in Yeast by Using Chromatin Immunoprecipitation with Lambda Exonuclease Digestion

We performed whole genome analysis of the DNA binding of five Saccharomyces cerevisiae transcription factors involved in lipid biosynthesis, Ino2, Ino4, Hap1, Oaf1 and Pip2, in response to four different environmental conditions. Using chromatin immunoprecipitation with lambda exonuclease digestion (ChIP-exo) we discovered a large number of so-far unidentified targets with nucleotide resolution. Based on the newly identified targets we document expanded functions for all five transcription factors, e.g. glutamate biosynthesis as a target of Oaf1 and Pip2. Moreover, condition-dependent binding of transcription factors in response to cell metabolic state, e.g. differential binding of Ino2 between fermentative and respiratory metabolic conditions was clearly suggested. Using our data we build a comprehensive transcriptional regulatory network for lipid metabolism in yeast.本研究针对五种参与脂质生物合成的酿酒酵母（Saccharomyces cerevisiae）转录因子Ino2、Ino4、Hap1、Oaf1及Pip2，在四种不同环境条件下的DNA结合模式开展了全基因组分析。采用lambda外切酶消化染色质免疫沉淀技术（ChIP-exo），我们以核苷酸分辨率鉴定出大量迄今未被发现的DNA结合靶标。基于新鉴定的靶标，我们阐明了上述五种转录因子的扩展功能，例如谷氨酸生物合成是Oaf1与Pip2的调控靶标。此外，研究清晰揭示了转录因子结合依赖于细胞代谢状态的特征，例如Ino2在发酵代谢与呼吸代谢两种条件下的差异结合现象。基于本研究产生的数据，我们构建了酿酒酵母脂质代谢的全面转录调控网络。