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The objective of this work was to study the expression of the TBX21, RORC, GATA3, NFKB1, MAPK8, and STAT3 genes responsible for the regulation of the differentiation of various T-helper subpopulations in individuals chronically exposed to radiation. The object of the study was peripheral blood cells obtained from 120 persons chronically exposed to radiation in a wide range of doses on the Techa River. The mean cumulative absorbed dose to red bone marrow in the examined exposed individuals was 742.7 ± 78.6 mGy (dose range, 73.5-3516.1 mGy); in the comparison group, 17.4 ± 2.2 mGy (dose range, 0.0-55.5 mGy). The subpopulation composition of T-helpers (Th1, Th2, and Th17) was analyzed by flow cytofluorometry. The relative mRNA content of the TBX21, RORC, GATA3, NFKB1, MAPK8, and STAT3 genes was estimated by real-time PCR. The study made it possible to note a decrease in the relative number of T-helpers 2 in the populations of T-helpers of the central memory in the group of chronically exposed persons compared to the comparison group. In the population of T-helpers of the central memory, a statistically significant increase in the relative number of T-helpers 1 was shown, depending on the accumulated absorbed dose to red bone marrow. No changes in mRNA expression of the studied genes were observed. The analysis of the correlation between the expression of GATA3, MAPK8, STAT3, RORC, and TBX21 mRNA and the relative number of cells in subpopulations of T-helper types 1, 2, and 17 in the examined people did not reveal statistically significant patterns.

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BACKGROUND: Microbial genome sequencing and analysis revealed the presence of abundant silent secondary metabolites biosynthetic gene clusters (BGCs) in streptomycetes. Activating these BGCs has great significance for discovering new compounds and novel biosynthetic pathways. RESULTS: In this study, we found that ovmZ and ovmW homologs, a pair of interdependent transcriptional regulators coding genes, are widespread in actinobacteria and closely associated with the biosynthesis of secondary metabolites. Through co-overexpression of native ovmZ and ovmW in Streptomyces neyagawaensis NRRL B-3092, a silent type II polyketide synthase (PKS) gene cluster was activated to produce gephyromycin A, tetrangomycin and fridamycin E with the yields of 22.3 ± 8.0 mg/L, 4.8 ± 0.5 mg/L and 20.3 ± 4.1 mg/L respectively in the recombinant strain of S.ne/pZnWn. However, expression of either ovmZ or ovmW failed to activate this gene cluster. Interestingly, overexpression of the heterologous ovmZ and ovmW pair from oviedomycin BGC of S. ansochromogenes 7100 also led to awakening of this silent angucyclinone BGC in S. neyagawaensis. CONCLUSION: A silent angucyclinone BGC was activated by overexpressing both ovmZ and ovmW in S. neyagawaensis. Due to the wide distribution of ovmZ and ovmW in the BGCs of actinobacteria, co-overexpression of ovmZ and ovmW could be a strategy for activating silent BGCs, thus stimulating the biosynthesis of secondary metabolites.

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A Mycobacterium smegmatis transcriptional regulator, MSMEG_5850, and its ortholog in M. tuberculosis, rv0775 were annotated as putative TetR Family Transcriptional Regulators. Our previous study revealed MSMEG_5850 is involved in global transcriptional regulation in M. smegmatis and the presence of gene product supported the survival of bacteria during nutritional starvation. Phylogenetic analysis showed that MSMEG_5850 diverged early in comparison to its counterparts in virulent strains. Therefore, the expression pattern of MSMEG_5850 and its counterpart, rv0775, was compared during various in-vitro growth and stress conditions. Expression of MSMEG_5850 was induced under different environmental stresses while no change in expression was observed under mid-exponential and stationary phases. No expression of rv0775 was observed under any stress condition tested, while the gene was expressed during the mid-exponential phase that declined in the stationary phase. The effect of MSMEG_5850 on the survival of M. smegmatis under stress conditions and growth pattern was studied using wild type, knockout, and supplemented strain. Deletion of MSMEG_5850 resulted in altered colony morphology, biofilm/pellicle formation, and growth pattern of M. smegmatis. The survival rate of wild-type MSMEG_5850 was higher in comparison to knockout under different environmental stresses. Overall, this study suggested the role of MSMEG_5850 in the growth and adaptation/survival of M. smegmatis under stress conditions.

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The memory CD8+ T cell pool contains phenotypically and transcriptionally heterogeneous subsets with specialized functions and recirculation patterns. Here, we examined the epigenetic landscape of CD8+ T cells isolated from seven non-lymphoid organs across four distinct infection models, alongside their circulating T cell counterparts. Using single-cell transposase-accessible chromatin sequencing (scATAC-seq), we found that tissue-resident memory T (TRM) cells and circulating memory T (TCIRC) cells develop along distinct epigenetic trajectories. We identified organ-specific transcriptional regulators of TRM cell development, including FOSB, FOS, FOSL1, and BACH2, and defined an epigenetic signature common to TRM cells across organs. Finally, we found that although terminal TEX cells share accessible regulatory elements with TRM cells, they are defined by TEX-specific epigenetic features absent from TRM cells. Together, this comprehensive data resource shows that TRM cell development is accompanied by dynamic transcriptome alterations and chromatin accessibility changes that direct tissue-adapted and functionally distinct T cell states.

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Many autism spectrum disorder (ASD)-associated genes act as transcriptional regulators (TRs). Chromatin immunoprecipitation sequencing (ChIP-seq) was used to identify the regulatory targets of ARID1B, BCL11A, FOXP1, TBR1, and TCF7L2, ASD-associated TRs in the developing human and mouse cortex. These TRs shared substantial overlap in the binding sites, especially within open chromatin. The overlap within a promoter region, 1-2,000 bp upstream of the transcription start site, was highly predictive of brain-expressed genes. This signature was observed in 96 out of 102 ASD-associated genes. In vitro CRISPRi against ARID1B and TBR1 delineated downstream convergent biology in mouse cortical cultures. After 8 days, NeuN+ and CALB+ cells were decreased, GFAP+ cells were increased, and transcriptomic signatures correlated with the postmortem brain samples from individuals with ASD. We suggest that functional convergence across five ASD-associated TRs leads to shared neurodevelopmental outcomes of haploinsufficient disruption.

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The lincoamide antibiotic lincomycin, derived from Streptomyces lincolnensis, is widely used for the treatment of infections caused by gram-positive bacteria. As a common global regulatory factor of GntR family, DasR usually exists as a regulatory factor that negatively regulates antibiotic synthesis in Streptomyces. However, the regulatory effect of DasR on lincomycin biosynthesis in S. lincolnensis has not been thoroughly investigated. The present study demonstrates that DasR functions as a positive regulator of lincomycin biosynthesis in S. lincolnensis, and its overexpression strain OdasR exhibits a remarkable 7.97-fold increase in lincomycin production compared to the wild-type strain. The effects of DasR overexpression could be attenuated by the addition of GlcNAc in the medium in S. lincolnensis. Combined with transcriptome sequencing and RT-qPCR results, it was found that most structural genes in GlcNAc metabolism and central carbon metabolism were up-regulated, but the lincomycin biosynthetic gene cluster (lmb) were down-regulated after dasR knock-out. However, DasR binding were detected with the DasR responsive elements (dre) of genes involved in GlcNAc metabolism pathway through electrophoretic mobility shift assay, while they were not observed in the lmb. These findings will provide novel insights for the genetic manipulation of S. lincolnensis to enhance lincomycin production. KEY POINTS: • DasR is a positive regulator that promotes lincomycin synthesis and does not affect spore production • DasR promotes lincomycin production through indirect regulation • DasR correlates with nutrient perception in S. lincolnensis.

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The enormous LysR-type transcriptional regulators (LTTRs), which are diversely distributed amongst prokaryotes, play crucial roles in transcription regulation of genes involved in basic metabolic pathways, virulence and stress resistance. However, the precise transcription activation mechanism of these genes by LTTRs remains to be explored. Here, we determine the cryo-EM structure of a LTTR-dependent transcription activation complex comprising of Escherichia coli RNA polymerase (RNAP), an essential LTTR protein GcvA and its cognate promoter DNA. Structural analysis shows two N-terminal DNA binding domains of GcvA (GcvA_DBD) dimerize and engage the GcvA activation binding sites, presenting the -35 element for specific recognition with the conserved σ70R4. In particular, the versatile C-terminal domain of α subunit of RNAP directly interconnects with GcvA_DBD, σ70R4 and promoter DNA, providing more interfaces for stabilizing the complex. Moreover, molecular docking supports glycine as one potential inducer of GcvA, and single molecule photobleaching experiments kinetically visualize the occurrence of tetrameric GcvA-engaged transcription activation complex as suggested for the other LTTR homologs. Thus, a general model for tetrameric LTTR-dependent transcription activation is proposed. These findings will provide new structural and functional insights into transcription activation of the essential LTTRs.

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BACKGROUND: The macrolide antibiotic avermectin, a natural product derived from Streptomyces avermitilis, finds extensive applications in agriculture, animal husbandry and medicine. The mtrA (sav_5063) gene functions as a transcriptional regulator belonging to the OmpR family. As a pleiotropic regulator, mtrA not only influences the growth, development, and morphological differentiation of strains but also modulates genes associated with primary metabolism. However, the regulatory role of MtrA in avermectin biosynthesis remains to be elucidated. RESULTS: In this study, we demonstrated that MtrA, a novel OmpR-family transcriptional regulator in S. avermitilis, exerts global regulator effects by negatively regulating avermectin biosynthesis and cell growth while positively controlling morphological differentiation. The deletion of the mtrA gene resulted in an increase in avermectin production, accompanied by a reduction in biomass and a delay in the formation of aerial hyphae and spores. The Electrophoretic Mobility Shift Assay (EMSA) revealed that MtrA exhibited binding affinity towards the upstream region of aveR, the intergenic region between aveA1 and aveA2 genes, as well as the upstream region of aveBVIII in vitro. These findings suggest that MtrA exerts a negative regulatory effect on avermectin biosynthesis by modulating the expression of avermectin biosynthesis cluster genes. Transcriptome sequencing and fluorescence quantitative PCR analysis showed that mtrA deletion increased the transcript levels of the cluster genes aveR, aveA1, aveA2, aveC, aveE, aveA4 and orf-1, which explains the observed increase in avermectin production in the knockout strain. Furthermore, our findings demonstrate that MtrA positively regulates the cell division and differentiation genes bldM and ssgC, while exerting a negative regulatory effect on bldD, thereby modulating the primary metabolic processes associated with cell division, differentiation and growth in S. avermitilis, consequently impacting avermectin biosynthesis. CONCLUSIONS: In this study, we investigated the negative regulatory effect of the global regulator MtrA on avermectin biosynthesis and its effects on morphological differentiation and cell growth, and elucidated its transcriptional regulatory mechanism. Our findings indicate that MtrA plays crucial roles not only in the biosynthesis of avermectin but also in coordinating intricate physiological processes in S. avermitilis. These findings provide insights into the synthesis of avermectin and shed light on the primary and secondary metabolism of S. avermitilis mediated by OmpR-family regulators.

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Resistance to infection by plant viruses involves proteins encoded by plant resistance (R) genes, viz., nucleotide-binding leucine-rich repeats (NLRs), immune receptors. These sensor NLRs are activated either directly or indirectly by viral protein effectors, in effector-triggered immunity, leading to induction of defense signaling pathways, resulting in the synthesis of numerous downstream plant effector molecules that inhibit different stages of the infection cycle, as well as the induction of cell death responses mediated by helper NLRs. Early events in this process involve recognition of the activation of the R gene response by various chaperones and the transport of these complexes to the sites of subsequent events. These events include activation of several kinase cascade pathways, and the syntheses of two master transcriptional regulators, EDS1 and NPR1, as well as the phytohormones salicylic acid, jasmonic acid, and ethylene. The phytohormones, which transit from a primed, resting states to active states, regulate the remainder of the defense signaling pathways, both directly and by crosstalk with each other. This regulation results in the turnover of various suppressors of downstream events and the synthesis of various transcription factors that cooperate and/or compete to induce or suppress transcription of either other regulatory proteins, or plant effector molecules. This network of interactions results in the production of defense effectors acting alone or together with cell death in the infected region, with or without the further activation of non-specific, long-distance resistance. Here, we review the current state of knowledge regarding these processes and the components of the local responses, their interactions, regulation, and crosstalk.

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Metal ions are essential trace elements for all living organisms and play critical catalytic, structural, and allosteric roles in many enzymes and transcription factors. Mycobacterium tuberculosis (MTB), as an intracellular pathogen, is usually found in host macrophages, where the bacterium can survive and replicate. One of the reasons why Tuberculosis (TB) is so difficult to eradicate is the continuous adaptation of its pathogen. It is capable of adapting to a wide range of harsh environmental stresses, including metal ion toxicity in the host macrophages. Altering the concentration of metal ions is the common host strategy to limit MTB replication and persistence. This review mainly focuses on transcriptional regulatory proteins in MTB that are involved in the regulation of metal ions such as iron, copper and zinc. The aim is to offer novel insights and strategies for screening targets for TB treatment, as well as for the development and design of new therapeutic interventions.

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Dapagliflozin (DAPA) are clinically effective in improving diabetic nephropathy (DN). However, whether and how chromatin accessibility changed by DN responds to DAPA treatment is unclear. Therefore, we performed ATAC-seq, RNA-seq, and weighted gene correlation network analysis to identify the chromatin accessibility, the messenger RNA (mRNA) expression, and the correlation between clinical phenotypes and mRNA expression using kidney from three mouse groups: db/m mice (Controls), db/db mice (case group), and those treated with DAPA (treatment group). RNA-Seq and ATAC-seq conjoint analysis revealed many overlapping pathways and networks suggesting that the transcriptional changes of DN and DAPA intervention largely occured dependently on chromatin remodeling. Specifically, the results showed that some key signal transduction pathways, such as immune dysfunction, glucolipid metabolism, oxidative stress and xenobiotic and endobiotic metabolism, were repeatedly enriched in the analysis of the RNA-seq data alone, as well as combined analysis with ATAC-seq data. Furthermore, we identified some candidate genes (UDP glucuronosyltransferase 1 family, Dock2, Tbc1d10c, etc.) and transcriptional regulators (KLF6 and GFI1) that might be associated with DN and DAPA restoration. These reversed genes and regulators confirmed that pathways related to immune response and metabolism pathways were critically involved in DN progression.

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Ionic homeostasis is essential for the survival and replication of Mycobacterium tuberculosis within its host. Low potassium ion concentrations trigger a transition of M. tuberculosis into dormancy. Our current knowledge of the transcriptional regulation mechanisms governing genes involved in potassium homeostasis remains limited. Potassium transport is regulated by the constitutive Trk system and the inducible Kdp system in M. tuberculosis. The two-component system KdpDE (also known as KdpD/KdpE) activates expression of the kdpFABC operon, encoding the four protein subunits of the Kdp potassium uptake system (KdpFABC). We show that, under potassium deficiency, expression of the two-component system senX3/regX3 is upregulated, and bacterial survival is compromised in a regX3-inactivated mutant, ΔregX3. Electrophoretic mobility shift assays (EMSAs), promoter reporter assays and chromatin immunoprecipitation (ChIP) show that RegX3 binds to the kdpDE promoter and activates it under potassium deficiency, whereas RegX3 (K204A), a DNA binding-deficient mutant, fails to bind to the promoter. Mutation of the RegX3 binding motifs on the kdpDE promoter abrogates RegX3 binding. In addition, EMSAs and ChIP assays show that RegX3 represses Rv0500A, a repressor of kdpFABC, by binding to consensus RegX3 binding motifs on the rv0500A promoter. Our findings provide important insight into two converging pathways regulated by RegX3; one in which it activates an activator of kdpFABC, and the other in which it represses a repressor of kdpFABC, during potassium insufficiency. This culminates in increased expression of the potassium uptake system encoded by kdpFABC, enabling bacterial survival. These results further expand the growing transcriptional network in which RegX3 serves as a central node to enable bacterial survival under stress.

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The Gram-negative Elizabethkingia express multiple antibiotic resistance and cause severe opportunistic infections. Vancomycin is commonly used to treat Gram-positive infections and has also been used to treat Elizabethkingia infections, even though Gram-negative organisms possess a vancomycin permeability barrier. Elizabethkingia anophelis appeared relatively vancomycin-susceptible and challenge with this drug led to morphological changes indicating cell lysis. In stark contrast, vancomycin growth challenge revealed that E. anophelis populations refractory to vancomycin emerged. In addition, E. anophelis vancomycin-selected mutants arose at high frequencies and demonstrated elevated vancomycin resistance and reduced susceptibility to other antimicrobials. All mutants possessed a SNP in a gene (vsr1 = vancomycin-susceptibility regulator 1) encoding a PadR family transcriptional regulator located in the putative operon vsr1-ORF551, which is conserved in other Elizabethkingia spp as well. This is the first report linking a padR homologue (vsr1) to antimicrobial resistance in a Gram-negative organism. We provide evidence to support that vsr1 acts as a negative regulator of vsr1-ORF551 and that vsr1-ORF551 upregulation is observed in vancomycin-selected mutants. Vancomycin-selected mutants also demonstrated reduced cell length indicating that cell wall synthesis is affected. ORF551 is a membrane-spanning protein with a small phage shock protein conserved domain. We hypothesize that since vancomycin-resistance is a function of membrane permeability in Gram-negative organisms, it is likely that the antimicrobial resistance mechanism in the vancomycin-selected mutants involves altered drug permeability.

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The opportunistic pathogen Pseudomonas aeruginosa infects cystic fibrosis (CF) patient airways and produces a virulence factor Cif that is associated with worse outcomes. Cif is an epoxide hydrolase that reduces cell-surface abundance of the cystic fibrosis transmembrane conductance regulator (CFTR) and sabotages pro-resolving signals. Its expression is regulated by a divergently transcribed TetR family transcriptional repressor. CifR represents the first reported epoxide-sensing bacterial transcriptional regulator, but neither its interaction with cognate operator sequences nor the mechanism of activation has been investigated. Using biochemical and structural approaches, we uncovered the molecular mechanisms controlling this complex virulence operon. We present here the first molecular structures of CifR alone and in complex with operator DNA, resolved in a single crystal lattice. Significant conformational changes between these two structures suggest how CifR regulates the expression of the virulence gene cif. Interactions between the N-terminal extension of CifR with the DNA minor groove of the operator play a significant role in the operator recognition of CifR. We also determined that cysteine residue Cys107 is critical for epoxide sensing and DNA release. These results offer new insights into the stereochemical regulation of an epoxide-based virulence circuit in a critically important clinical pathogen.

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In a previous study, the novel gene cluster cehGHI was found to be involved in salicylate degradation through the CoA-mediated pathway in Rhizobium sp. strain X9 (Mol Microbiol 116:783-793, 2021). In this study, an IclR family transcriptional regulator CehR4 was identified. In contrast to other regulators involved in salicylate degradation, cehR4 forms one operon with the gentisyl-CoA thioesterase gene cehI, while cehG and cehH (encoding salicylyl-CoA ligase and salicylyl-CoA hydroxylase, respectively) form another operon. cehGH and cehIR4 are divergently transcribed, and their promoters overlap. The results of the electrophoretic mobility shift assay and DNase I footprinting showed that CehR4 binds to the 42-bp motif between genes cehH and cehI, thus regulating transcription of cehGH and cehIR4. The repeat sequences IR1 (5'-TTTATATAAA-3') and IR2 (5'-AATATAGAAA-3') in the motif are key sites for CehR4 binding. The arrangement of cehGH and cehIR4 and the conserved binding motif of CehR4 were also found in other bacterial genera. The results disclose the regulatory mechanism of salicylate degradation through the CoA pathway and expand knowledge about the systems controlled by IclR family transcriptional regulators.IMPORTANCEThe long-term residue of aromatic compounds in the environment has brought great threat to the environment and human health. Microbial degradation plays an important role in the elimination of aromatic compounds in the environment. Salicylate is a common intermediate metabolite in the degradation of various aromatic compounds. Recently, Rhizobium sp. strain X9, capable of degrading the pesticide carbaryl, was isolated from carbaryl-contaminated soil. Salicylate is the intermediate metabolite that appeared during the degradation of carbaryl, and a novel salicylate degradation pathway and the involved gene cluster cehGHIR4 have been identified. This study identified and characterized the IclR transcription regulator CehR4 that represses transcription of cehGHIR4 gene cluster. Additionally, the genetic arrangements of cehGH and cehIR4 and the binding sites of CehR4 were also found in other bacterial genera. This study provides insights into the biodegradation of salicylate and provides an application in the bioremediation of aromatic compound-contaminated environments.

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Antiretroviral therapy (ART) has dramatically improved the prognosis for people living with HIV-1, but a cure remains elusive. The largest barrier to a cure is the presence of a long-lived latent reservoir that persists within a heterogenous mix of cell types and anatomical compartments. Efforts to eradicate the latent reservoir have primarily focused on latency reversal strategies. However, new work has demonstrated that the majority of the long-lived latent reservoir is established near the time of ART initiation, suggesting that it may be possible to pair an intervention with ART initiation to prevent the formation of a sizable fraction of the latent reservoir. Subsequent treatment with latency reversal agents, in combination with immune clearance agents, may then be a more tractable strategy for fully clearing the latent reservoir in people newly initiating ART. Here, we summarize molecular mechanisms of latency establishment and maintenance, ongoing efforts to develop effective latency reversal agents, and newer efforts to design latency prevention agents. An improved understanding of the molecular mechanisms involved in both the establishment and maintenance of latency will aid in the development of new latency prevention and reversal approaches to ultimately eradicate the latent reservoir.

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In Pseudomonas aeruginosa (P. aeruginosa), transcription factors (TFs) are important mediators in the genetic regulation of adaptability and pathogenicity to respond to multiple environmental stresses and host defences. The P. aeruginosa genome harbours 371 putative TFs; of these, about 70 have been shown to regulate virulence-associated phenotypes by binding to the promoters of their target genes. Over the past three decades, several techniques have been applied to identify TF binding sites on the P. aeruginosa genome, and an atlas of TF binding patterns has been mapped. The virulence-associated regulons of TFs show complex crosstalk in P. aeruginosa's regulatory network. In this review, we summarise the recent literature on TF regulatory networks involved in the quorum-sensing system, biofilm formation, pyocyanin synthesis, motility, the type III secretion system, the type VI secretion system, and oxidative stress responses. We discuss future perspectives that could provide insights and targets for preventing clinical infections caused by P. aeruginosa based on the global regulatory network of transcriptional regulators.

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Molecules involved in drug resistance can be targeted for better therapeutic efficacies. Research on midkine (MDK) has escalated in the last few decades, which affirms a positive correlation between disease progression and MDK expression in most cancers and indicates its association with multi-drug resistance in cancer. MDK, a secretory cytokine found in blood, can be exploited as a potent biomarker for the non-invasive detection of drug resistance expressed in various cancers and, thereby, can be targeted. We summarize the current information on the involvement of MDK in drug resistance, and transcriptional regulators of its expression and highlight its potential as a cancer therapeutic target.

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The MyoD gene was duplicated during the teleost whole genome duplication and, while a second MyoD gene (MyoD2) was subsequently lost from the genomes of some lineages (including zebrafish), many fish lineages (including Alcolapia species) have retained both MyoD paralogues. Here we reveal the expression patterns of the two MyoD genes in Oreochromis (Alcolapia) alcalica using in situ hybridisation. We report our analysis of MyoD1 and MyoD2 protein sequences from 54 teleost species, and show that O. alcalica, along with some other teleosts, include a polyserine repeat between the amino terminal transactivation domains (TAD) and the cysteine-histidine rich region (H/C) in MyoD1. The evolutionary history of MyoD1 and MyoD2 is compared to the presence of this polyserine region using phylogenetics, and its functional relevance is tested using overexpression in a heterologous system to investigate subcellular localisation, stability, and activity of MyoD proteins that include and do not include the polyserine region.

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There is an unmet medical need for effective treatments against Mycobacterium abscessus infections. Although advanced molecular genetic tools to validate drug targets and resistance of M. abscessus exist, the practical design and construction of plasmids are relatively laborious and time-consuming. Thus, for this purpose, we used CRISPR interference (CRISPRi) combined with catalytically deactivated Cas9 to inhibit the gene expression of a predicted LysR-type transcriptional regulator gene, MAB_0055c, in M. abscessus and evaluated its contribution to the development of drug resistance. Our results showed that silencing the MAB_0055c gene lead to increased rifamycin susceptibility depending on the hydroquinone moiety. These results demonstrate that CRISPRi is an excellent approach for studying drug resistance in M. abscessus. IMPORTANCE In this study, we utilized CRISPR interference (CRISPRi) to specifically target the MAB_0055c gene in M. abscessus, a bacterium that causes difficult-to-treat infections. The study found that silencing the gene lead to increased rifabutin and rifalazil susceptibility. This study is the first to establish a link between the predicted LysR-type transcriptional regulator gene and antibiotic resistance in mycobacteria. These findings underscore the potential of using CRISPRi as a tool for elucidating resistance mechanisms, essential drug targets, and drug mechanisms of action, which could pave the way for more effective treatments for M. abscessus infections. The results of this study could have important implications for the development of new therapeutic options for this challenging-to-treat bacterial infection.

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