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Background: The regulation of multiple gene expression is pivotal for metabolic engineering. Although CRISPR interference (CRISPRi) has been extensively utilized for multi-gene regulation, the construction of numerous single-guide RNA (sgRNA) expression plasmids for combinatorial regulation remains a significant challenge.
Results: In this study, we developed a combinatorial repression system for multiple genes by optimizing the expression of multi-sgRNA with various inducible promoters in Escherichia coli. We designed a modified Golden Gate Assembly method to rapidly construct the sgRNA expression plasmid p3gRNA-LTA. By optimizing both the promoter and the sgRNA handle sequence, we substantially mitigated undesired repression caused by the leaky expression of sgRNA. This method facilitates the rapid assessment of the effects of various inhibitory combinations on three genes by simply adding different inducers. Using the biosynthesis of N-acetylneuraminic acid (NeuAc) as an example, we found that the optimal combinatorial inhibition of the pta, ptsI, and pykA genes resulted in a 2.4-fold increase in NeuAc yield compared to the control.
Conclusion: We anticipate that our combinatorial repression system will greatly simplify the regulation of multiple genes and facilitate the fine-tuning of metabolic flow in the engineered strains.
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http://dx.doi.org/10.1186/s12934-025-02697-x | DOI Listing |
FEMS Microbiol Rev
September 2025
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
Histone-like nucleoid structuring protein H-NS plays a pivotal role in orchestrating bacterial chromatin and regulating horizontal gene transfer (HGT) elements. In response to environmental signals, H-NS undergoes dynamic post-translational modifications (PTMs) that resemble the epigenetic codes of eukaryotic histones. This review explores how environmental cues regulate PTMs at specific sites within distinct domains of H-NS, thereby modulating its oligomerization and DNA-binding capabilities to reprogram bacterial responses.
View Article and Find Full Text PDFNucleic Acids Res
August 2025
Institute of Molecular Biology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria.
Accurate sensing of cellular iron levels is vital, as this metal is essential but toxic in excess. The iron-sensing transcription factor HapX is crucial for virulence of Aspergillus fumigatus, the predominant human mold pathogen. Its absence impairs growth under iron limitation and excess, but not under moderate iron availability, suggesting that HapX switches between three states to adapt to varying iron availability.
View Article and Find Full Text PDFSci Rep
August 2025
Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
Unlabelled: Comprehensive epigenomic studies in multiple myeloma (MM) that unravel the connections between major epigenetic regulators, their intertwined collaboration and the potential of combinatorial targeting remain limited. Utilizing ChIP-seq, ATAC-seq, RNA-seq, and DNA methylation (DNAme) data, we generated whole-genome chromatin annotations from normal plasma cells and MM patients, revealing epigenomic re-configuration affecting downstream genes involved in tumour growth and survival. Primary MM samples showed global DNA hypomethylation but site-specific hypermethylation was observed at transcription start sites, promoters, and enhancers.
View Article and Find Full Text PDFMol Cell
September 2025
Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK; Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK. Electronic address:
Multivalent protein-chromatin interactions facilitated by higher-order protein assemblies are emerging as a crucial theme in eukaryotic gene regulation. However, understanding the underlying mechanisms in their functional context remains challenging. Arabidopsis VEL proteins assemble biomolecular condensates by head-to-tail polymerization.
View Article and Find Full Text PDFBiomark Res
July 2025
Lymphocyte Development and Disease Group, Josep Carreras Leukaemia Research Institute (IJC), Ctra de Can Ruti, Camí de les Escoles, s/n, 08916, Badalona, Barcelona, Spain.
Background: Infants diagnosed with B cell acute lymphoblastic leukemia (B-ALL) and t(4;11) chromosomal rearrangement display poor therapeutic response, associated to the low expression of B lymphocyte factor HDAC7. This study was conceived to identify a therapeutic strategy for t(4;11) B-ALL that restores optimal HDAC7 expression.
Methods: A multiomics approach in a large infant pro-B-ALL cohort was employed to identify HDAC7's repression mechanism.