State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.
Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
Appl Environ Microbiol. 2018 Jul 17;84(15). doi: 10.1128/AEM.00781-18. Print 2018 Aug 1.
is a promising microorganism for the production of organic acids. Here, we report deletion and quantitative-expression approaches to elucidate the role of Med3AB (Med3AB), a subunit of the mediator transcriptional coactivator, in regulating cell growth. Deletion of Med3AB caused an 8.6% decrease in final biomass based on growth curve plots and 10.5% lower cell viability. Based on transcriptomics data, the reason for this growth defect was attributable to changes in expression of genes involved in pyruvate and acetyl-coenzyme A (CoA)-related metabolism in a Δ strain. Furthermore, the mRNA level of acetyl-CoA synthetase was downregulated after deleting , resulting in 22.8% and 21% lower activity of acetyl-CoA synthetase and cellular acetyl-CoA, respectively. Additionally, the mRNA level of Cln3, whose expression depends on acetyl-CoA, was 34% lower in this strain. As a consequence, the cell size and budding index in the Δ strain were both reduced. Conversely, overexpression of led to 16.8% more acetyl-CoA and 120% higher Cln3 mRNA levels, as well as 19.1% larger cell size and a 13.3% higher budding index than in wild-type cells. Taken together, these results suggest that Med3AB regulates cell growth in by coordinating homeostasis between cellular acetyl-CoA and Cln3. This study demonstrates that Med3AB can regulate cell growth in by coordinating the homeostasis of cellular acetyl-CoA metabolism and the cell cycle cyclin Cln3. Specifically, we report that Med3AB regulates the cellular acetyl-CoA level, which induces the transcription of , finally resulting in alterations to the cell size and budding index. In conclusion, we report that Med3AB functions as a wheel responsible for driving cellular acetyl-CoA metabolism, indirectly inducing the transcription of and coordinating cell growth. We propose that Mediator subunits may represent a vital regulatory target modulating cell growth in .
是一种很有前途的生产有机酸的微生物。在这里，我们报告了删除和定量表达的方法，以阐明中介转录共激活因子亚基 Med3AB（Med3AB）在调节细胞生长中的作用。Med3AB 的缺失导致根据生长曲线图谱最终生物量减少 8.6%，细胞活力降低 10.5%。基于转录组学数据，这种生长缺陷的原因归因于参与丙酮酸和乙酰辅酶 A（CoA）相关代谢的基因表达的变化。此外，在Δ菌株中，乙酰辅酶 A 合成酶的 mRNA 水平下调，导致乙酰辅酶 A 合成酶和细胞内乙酰辅酶 A 的活性分别降低 22.8%和 21%。此外，该菌株中依赖于乙酰辅酶 A 的 Cln3 的 mRNA 水平降低了 34%。因此，Δ菌株的细胞大小和出芽指数均降低。相反，过表达 Med3AB 导致乙酰辅酶 A 增加 16.8%，Cln3 mRNA 水平增加 120%，细胞大小增加 19.1%，出芽指数增加 13.3%，高于野生型细胞。总之，这些结果表明 Med3AB 通过协调细胞内乙酰辅酶 A 和 Cln3 之间的平衡来调节酵母细胞的生长。这项研究表明，Med3AB 通过协调细胞内乙酰辅酶 A 代谢和细胞周期周期蛋白 Cln3 的平衡来调节酵母细胞的生长。具体而言，我们报告 Med3AB 调节细胞内乙酰辅酶 A 水平，从而诱导 Cln3 的转录，最终导致细胞大小和出芽指数的改变。总之，我们报告 Med3AB 作为一个负责驱动细胞内乙酰辅酶 A 代谢的轮，间接诱导 Cln3 的转录并协调细胞生长。我们提出 Mediator 亚基可能代表调节酵母细胞生长的重要调控靶标。
