Baur Saskia Tabea, Poehlein Anja, Renz Niklas Jan, Hollitzer Stefanie Karolina, Montoya Solano José David, Schiel-Bengelsdorf Bettina, Daniel Rolf, Dürre Peter
Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany.
Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany.
Front Genet. 2022 Aug 11;13:966643. doi: 10.3389/fgene.2022.966643. eCollection 2022.
Solvents such as butanol are important platform chemicals and are often produced from petrochemical sources. Production of butanol and other compounds from renewable and sustainable resources can be achieved by solventogenic bacteria, such as the hyper-butanol producer . Its operon consists of the genes encoding butyraldehyde dehydrogenase, CoA transferase, and acetoacetate decarboxylase (, , , ) and the gene products are involved in butanol and acetone formation. It is important to understand its regulation to further optimize the solvent production. In this study, a new long non-coding antisense transcript complementary to the complete operon, now called Assolrna, was identified by transcriptomic analysis and the regulatory mechanism of Assolrna was investigated. For this purpose, the promoter-exchange strain ΔP P was constructed. Additionally, Assolrna was expressed plasmid-based under control of the native P promoter and the lactose-inducible P promoter in both the wild type and the promoter-exchange strain. Solvent formation was strongly decreased for all strains based on ΔP P and growth could not be restored by plasmid-based complementation of the exchanged promoter. Interestingly, very little mRNA expression was detected in the strain ΔP P lacking Assolrna expression. Butanol titers were further increased for the overexpression strain [pMTL83151__P ] compared to the wild type. These results suggest that Assolrna has a positive effect on operon expression. Therefore, a possible stabilization mechanism of the mRNA by Assolrna under physiological concentrations is proposed.
丁醇等溶剂是重要的平台化学品，通常由石化资源生产。由可再生和可持续资源生产丁醇及其他化合物可通过产溶剂细菌实现，比如高产丁醇菌。其操纵子由编码丁醛脱氢酶、辅酶A转移酶和乙酰乙酸脱羧酶的基因（、、、）组成，这些基因产物参与丁醇和丙酮的形成。了解其调控机制对于进一步优化溶剂生产很重要。在本研究中，通过转录组分析鉴定出一种与完整操纵子互补的新型长链非编码反义转录本，现称为Assolrna，并对Assolrna的调控机制进行了研究。为此，构建了启动子交换菌株ΔP P 。此外，在野生型和启动子交换菌株中，Assolrna在天然P 启动子和乳糖诱导型P 启动子的控制下基于质粒表达。基于ΔP P 的所有菌株的溶剂形成均显著降低，并且通过交换启动子的基于质粒的互补无法恢复生长。有趣的是，在缺乏Assolrna表达的菌株ΔP P 中检测到极少的mRNA表达。与野生型相比，过表达菌株[pMTL83151__P ]的丁醇滴度进一步提高。这些结果表明Assolrna对操纵子表达有积极作用。因此，提出了一种在生理浓度下Assolrna对mRNA的可能稳定机制。
