Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory
Abstract Background Aspergillus niger is an important industrial filamentous fungus used to produce organic acids and enzymes. A wide dynamic range of promoters, particularly strong promoters, are required for fine-tuning the regulation of gene expression to balance metabolic flux and achieve the hi...
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BMC
2025-01-01
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| Series: | Microbial Cell Factories |
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| Online Access: | https://doi.org/10.1186/s12934-025-02642-y |
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| author | Xiaomei Zheng Yuting Guo Meiling Chen Yudan Lu Yimou Du Yu Lei Ping Zheng Jibin Sun |
| author_facet | Xiaomei Zheng Yuting Guo Meiling Chen Yudan Lu Yimou Du Yu Lei Ping Zheng Jibin Sun |
| author_sort | Xiaomei Zheng |
| collection | DOAJ |
| description | Abstract Background Aspergillus niger is an important industrial filamentous fungus used to produce organic acids and enzymes. A wide dynamic range of promoters, particularly strong promoters, are required for fine-tuning the regulation of gene expression to balance metabolic flux and achieve the high yields of desired products. However, the limited understanding of promoter architectures and activities restricts the efficient transcription regulation of targets in strain engineering in A. niger. Results In this study, we identified two functional upstream activation sequences (UAS) located upstream of the core promoters of highly expressed genes in A. niger. We constructed and characterized a synthetic promoter library by fusing the efficient UAS elements upstream of the strong constitute PgpdA promoter in A. niger. It demonstrated that the strength of synthetic promoters was fine-tuned with a wide range by tandem assembly of the UAS elements. Notably, the most potent promoter exhibited 5.4-fold higher activity than the strongest PgpdA promoter reported previously, significantly extending the range of strong promoters. Using citric acid production as a case study, we employed the synthetic promoter library to enhance citric acid efflux by regulating the cexA expression in A. niger. It showed a 1.6-2.3-fold increase in citric acid production compared to the parent strain, achieving a maximum titer of 145.3 g/L. Conclusions This study proved that the synthetic promoter library was a powerful toolkit for precise tuning of transcription in A. niger. It also underscores the potential of promoter engineering for gene regulation in strain improvement of fungal cell factories. |
| format | Article |
| id | doaj-art-cb23a9e614c94e12841cffa850ade10f |
| institution | Kabale University |
| issn | 1475-2859 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Microbial Cell Factories |
| spelling | doaj-art-cb23a9e614c94e12841cffa850ade10f2025-01-19T12:44:18ZengBMCMicrobial Cell Factories1475-28592025-01-0124111310.1186/s12934-025-02642-yPromoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factoryXiaomei Zheng0Yuting Guo1Meiling Chen2Yudan Lu3Yimou Du4Yu Lei5Ping Zheng6Jibin Sun7Tianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesAbstract Background Aspergillus niger is an important industrial filamentous fungus used to produce organic acids and enzymes. A wide dynamic range of promoters, particularly strong promoters, are required for fine-tuning the regulation of gene expression to balance metabolic flux and achieve the high yields of desired products. However, the limited understanding of promoter architectures and activities restricts the efficient transcription regulation of targets in strain engineering in A. niger. Results In this study, we identified two functional upstream activation sequences (UAS) located upstream of the core promoters of highly expressed genes in A. niger. We constructed and characterized a synthetic promoter library by fusing the efficient UAS elements upstream of the strong constitute PgpdA promoter in A. niger. It demonstrated that the strength of synthetic promoters was fine-tuned with a wide range by tandem assembly of the UAS elements. Notably, the most potent promoter exhibited 5.4-fold higher activity than the strongest PgpdA promoter reported previously, significantly extending the range of strong promoters. Using citric acid production as a case study, we employed the synthetic promoter library to enhance citric acid efflux by regulating the cexA expression in A. niger. It showed a 1.6-2.3-fold increase in citric acid production compared to the parent strain, achieving a maximum titer of 145.3 g/L. Conclusions This study proved that the synthetic promoter library was a powerful toolkit for precise tuning of transcription in A. niger. It also underscores the potential of promoter engineering for gene regulation in strain improvement of fungal cell factories.https://doi.org/10.1186/s12934-025-02642-yAspergillus NigerSynthetic promoterUpstream activation sequenceFluorescence proteinCitric acid production |
| spellingShingle | Xiaomei Zheng Yuting Guo Meiling Chen Yudan Lu Yimou Du Yu Lei Ping Zheng Jibin Sun Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory Microbial Cell Factories Aspergillus Niger Synthetic promoter Upstream activation sequence Fluorescence protein Citric acid production |
| title | Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory |
| title_full | Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory |
| title_fullStr | Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory |
| title_full_unstemmed | Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory |
| title_short | Promoter engineering with programmable upstream activating sequences in Aspergillus Niger cell factory |
| title_sort | promoter engineering with programmable upstream activating sequences in aspergillus niger cell factory |
| topic | Aspergillus Niger Synthetic promoter Upstream activation sequence Fluorescence protein Citric acid production |
| url | https://doi.org/10.1186/s12934-025-02642-y |
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