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Schlüter L, Busche T, Bondzio L, Hütten A, Niehaus K, Schneiker-Bekel S, Pühler A, Kalinowski J. Sigma Factor Engineering in Actinoplanes sp. SE50/110: Expression of the Alternative Sigma Factor Gene ACSP50_0507 (σH As) Enhances Acarbose Yield and Alters Cell Morphology. Microorganisms 2024; 12:1241. [PMID: 38930623 PMCID: PMC11205660 DOI: 10.3390/microorganisms12061241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Sigma factors are transcriptional regulators that are part of complex regulatory networks for major cellular processes, as well as for growth phase-dependent regulation and stress response. Actinoplanes sp. SE50/110 is the natural producer of acarbose, an α-glucosidase inhibitor that is used in diabetes type 2 treatment. Acarbose biosynthesis is dependent on growth, making sigma factor engineering a promising tool for metabolic engineering. ACSP50_0507 is a homolog of the developmental and osmotic-stress-regulating Streptomyces coelicolor σHSc. Therefore, the protein encoded by ACSP50_0507 was named σHAs. Here, an Actinoplanes sp. SE50/110 expression strain for the alternative sigma factor gene ACSP50_0507 (sigHAs) achieved a two-fold increased acarbose yield with acarbose production extending into the stationary growth phase. Transcriptome sequencing revealed upregulation of acarbose biosynthesis genes during growth and at the late stationary growth phase. Genes that are transcriptionally activated by σHAs frequently code for secreted or membrane-associated proteins. This is also mirrored by the severely affected cell morphology, with hyperbranching, deformed and compartmentalized hyphae. The dehydrated cell morphology and upregulation of further genes point to a putative involvement in osmotic stress response, similar to its S. coelicolor homolog. The DNA-binding motif of σHAs was determined based on transcriptome sequencing data and shows high motif similarity to that of its homolog. The motif was confirmed by in vitro binding of recombinantly expressed σHAs to the upstream sequence of a strongly upregulated gene. Autoregulation of σHAs was observed, and binding to its own gene promoter region was also confirmed.
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Affiliation(s)
- Laura Schlüter
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany; (L.S.); (S.S.-B.)
| | - Tobias Busche
- Technology Platform Genomics, Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany;
- Medical School East Westphalia-Lippe, Bielefeld University, 33594 Bielefeld, Germany
| | - Laila Bondzio
- Faculty of Physics, Bielefeld University, 33594 Bielefeld, Germany; (L.B.); (A.H.)
| | - Andreas Hütten
- Faculty of Physics, Bielefeld University, 33594 Bielefeld, Germany; (L.B.); (A.H.)
| | - Karsten Niehaus
- Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, 33594 Bielefeld, Germany;
| | - Susanne Schneiker-Bekel
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany; (L.S.); (S.S.-B.)
- Genome Research of Industrial Microorganisms, Center for Biotechnology (CeBiTec), Bielefeld University, 33594 Bielefeld, Germany;
| | - Alfred Pühler
- Genome Research of Industrial Microorganisms, Center for Biotechnology (CeBiTec), Bielefeld University, 33594 Bielefeld, Germany;
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany; (L.S.); (S.S.-B.)
- Technology Platform Genomics, Center for Biotechnology, Bielefeld University, 33594 Bielefeld, Germany;
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Li Z, Yang S, Zhang Z, Wu Y, Tang J, Wang L, Chen S. Enhancement of acarbose production by genetic engineering and fed-batch fermentation strategy in Actinoplanes sp. SIPI12-34. Microb Cell Fact 2022; 21:240. [DOI: 10.1186/s12934-022-01969-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/11/2022] [Indexed: 11/25/2022] Open
Abstract
Abstract
Background
Acarbose, as an alpha-glucosidase inhibitor, is widely used clinically to treat type II diabetes. In its industrial production, Actinoplanes sp. SE50/110 is used as the production strain. Lack of research on its regulatory mechanisms and unexplored gene targets are major obstacles to rational strain design. Here, transcriptome sequencing was applied to uncover more gene targets and rational genetic engineering was performed to increase acarbose production.
Results
In this study, with the help of transcriptome information, a TetR family regulator (TetR1) was identified and confirmed to have a positive effect on the synthesis of acarbose by promoting the expression of acbB and acbD. Some genes with low expression levels in the acarbose biosynthesis gene cluster were overexpressed and this resulted in a significant increase in acarbose yield. In addition, the regulation of metabolic pathways was performed to retain more glucose-1-phosphate for acarbose synthesis by weakening the glycogen synthesis pathway and strengthening the glycogen degradation pathway. Eventually, with a combination of multiple strategies and fed-batch fermentation, the yield of acarbose in the engineered strain increased 58% compared to the parent strain, reaching 8.04 g/L, which is the highest fermentation titer reported.
Conclusions
In our research, acarbose production had been effectively and steadily improved through genetic engineering based on transcriptome analysis and fed-batch culture strategy.
Graphical Abstract
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