National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
FEMS Yeast Res. 2018 Feb 1;18(1). doi: 10.1093/femsyr/fox081.
The efficient promoter of alcohol oxidase 1 (PAOX1) in methylotrophic yeast Pichia pastoris is strictly induced by methanol but repressed by glycerol with an unclear molecular mechanism. In the present study, the gene of a previously characterized transmembrane protein glycerol transporter 1 (GT1) of P. pastoris GS115 was deleted by homologous recombination. Transcriptional profiles of the mutant (gt1Δ) and wild type (WT) were compared with different carbon sources (glycerol, methanol and glycerol-methanol mix) at various time points using high-throughput RNA-Seq techniques. We determined that the loss of glycerol transporter 1 (Gt1p) could relieve catabolite repression in the glycerol-methanol mixed medium and shared a similar transcriptional profile with the WT in methanol medium. By calculating the common differentially expressed genes in three distinct paired groups, genes involved in the stress response, nutrition deprivation and translational process were identified, explaining the potential roles of glycerol in the regulation of methanol metabolism. Based on weighted gene co-expression network analysis, the relationship between biological traits and the transcriptional profile was established. With the support of published research and our data, we propose two possible regulatory pathways that are involved in the regulation of catabolite repression (adenosine 5΄-monophosphate (AMP)-activated protein kinase /SNF1 and Mitogen-activated protein kinase/HOG), thereby providing potential targets for both research and industrial strain improvement.
甲醇氧化酶 1（PAOX1）在甲醇营养型酵母巴斯德毕赤酵母中的高效启动子严格受甲醇诱导，而受甘油抑制，但分子机制尚不清楚。在本研究中，通过同源重组技术敲除了毕赤酵母 GS115 中先前鉴定的跨膜蛋白甘油转运蛋白 1（GT1）的基因。在不同的时间点，使用高通量 RNA-Seq 技术比较了突变体（gt1Δ）和野生型（WT）在不同碳源（甘油、甲醇和甘油-甲醇混合）下的转录谱。我们发现甘油转运蛋白 1（Gt1p）的缺失可以减轻甘油-甲醇混合培养基中的分解代谢物阻遏作用，并且在甲醇培养基中与 WT 具有相似的转录谱。通过计算三个不同配对组中共同差异表达的基因，鉴定出参与应激反应、营养剥夺和翻译过程的基因，解释了甘油在甲醇代谢调控中的潜在作用。基于加权基因共表达网络分析，建立了生物特征与转录谱之间的关系。结合已发表的研究和我们的数据，我们提出了两种可能的调控途径，它们涉及分解代谢物阻遏的调节（腺苷酸 5'-单磷酸（AMP）激活蛋白激酶/SNF1 和丝裂原激活蛋白激酶/HOG），从而为研究和工业菌株改良提供了潜在的靶点。
