Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
University of Chinese Academy of Sciences, Beijing, China.
Appl Environ Microbiol. 2018 Apr 2;84(8). doi: 10.1128/AEM.00114-18. Print 2018 Apr 15.
The master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to a -acting catabolite-responsive element (), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual- motif that is employed by the CcpA in , a typical solventogenic species, for autoregulation. Two sites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual- motif, , in the promoter region, positively regulates transcription, whereas , in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA bound more strongly than , the assay showed that -based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation of was made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA in and, moreover, contributes a new engineering strategy for this industrial strain. CcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual- motif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular performance, providing a new useful strategy in genetic engineering of Since CcpA is widespread in Gram-positive bacteria, including pathogens, this dual--based CcpA autoregulation would be valuable for increasing our understanding of CcpA-based global regulation in bacteria.
主调控因子 CcpA（分解代谢物控制蛋白 A）管理着一个庞大而复杂的调控网络，该网络对于革兰氏阳性菌的细胞生理学和新陈代谢至关重要。尽管 CcpA 可以通过结合 - 作用的分解代谢物响应元件 () 来影响靶基因的表达，但 CcpA 的表达是如何受到调控的仍未得到充分探索。在这里，我们报道了一种新型双 - 基序，该基序被用于典型的溶剂生成 物种中的 CcpA 进行自我调控。两个 位点参与 CcpA 的自我调控，它们位于 CcpA 的启动子和编码区。在这个双 - 基序中，位于启动子区域的 正向调节 CcpA 的转录，而位于编码区的 负向调节此转录，从而实现 CcpA 的双向自我调控。尽管 CcpA 与 结合得更强，但 测定表明，基于 - 的抑制在整个发酵过程中占主导地位，从而调节 CcpA 的自我调控。最后，在编码区中对 进行了同义突变，实现了细胞内 CcpA 表达的增加和细胞性能的提高。这项研究为 CcpA 在 中的调控作用提供了新的见解，此外，为该工业菌株贡献了一种新的工程策略。CcpA 被认为是革兰氏阳性菌中的关键转录因子。然而，细胞内 CcpA 水平是否以及如何受到调控仍不清楚，这对于维持正常的细胞生理学和新陈代谢可能至关重要。我们在这里发现，CcpA 采用双 - 基序进行自我调控，从而在整个发酵过程中动态控制自身表达水平。这一发现回答了上述问题，并填补了我们对 CcpA 调控网络理解的空白。干扰 CcpA 的自我调控会导致细胞性能的提高，为 的遗传工程提供了一种新的有用策略。由于 CcpA 在革兰氏阳性菌中广泛存在，包括病原体，因此这种基于双 - 的 CcpA 自我调控对于增加我们对细菌中基于 CcpA 的全局调控的理解将是有价值的。
