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Results for “Transposase”

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At least 19 recordsLinked to original sources

PubMed2003

Alternative interactions between the Tn7 transposase and the Tn7 target DNA binding protein regulate target immunity and transposition.

The Tn7 transposon avoids inserting into a target DNA that contains a pre-existing copy of Tn7. This phenomenon, known as 'target immunity', is established when TnsB, a Tn7 transposase subunit, binds to Tn7 sequences in the target DNA and mediates displacement of TnsC, a critical transposase activator, from the DNA. Paradoxically, TnsB-TnsC interactions are also required to promote transposon insertion. We have probed Tn7 target immunity by isolating TnsB mutants that mediate more frequent insertions into a potentially immune target DNA because they fail to provoke dissociation of TnsC from the DNA. We show that a single region of TnsB mediates the TnsB-TnsC interaction that underlies both target immunity and transposition, but that TnsA, the other transposase subunit, channels the TnsB-TnsC interaction toward transposition.

Amino Acid Sequence↗

PubMed2026

Duplex-Indel: a Snakemake pipeline for somatic Indel calling in Tn5 transposase-based duplex sequencing data.

SUMMARY: Duplex-Indel is a novel Snakemake workflow for detecting somatic small insertions and deletions (Indels) from Tn5 transposase-based duplex sequencing data. Duplex-Indel enhances the accuracy of mutation calling at the single-molecule level by requiring consensus support from both DNA strands for each somatic Indel, minimizing confounding from technical artifacts. Duplex-Indel extends somatic mutation calling in Tn5 transposase-based duplex sequencing data to include Indels. We have demonstrated the accuracy and robustness of Duplex-Indel using cancer cell lines. AVAILABILITY AND IMPLEMENTATION: Source code and documentation are available under the MIT license on GitHub at https://github.com/ealee-lab/duplex-indel and archived on Zenodo at https://doi.org/10.5281/zenodo.19228799.

Transposases↗

PubMed2025

ATAC-seq in Emerging Model Organisms: Challenges and Strategies.

The Assay for Transposase-Accessible Chromatin with sequencing (ATAC-seq) is a versatile and widely utilized method for identifying potential regulatory regions, such as promoters and enhancers, within a genome. ATAC-seq has been successfully applied to a wide range of established and emerging model organisms. However, implementing this method in emerging model systems, such as arthropods, can be challenging due to several factors that influence data quality. These factors include the availability of a sufficient amount and quality of tissue or cells, the need for species- and tissue-specific protocol optimization, the completeness and accuracy of the reference genome, and the quality of the genome annotation. In this article, we emphasize the key steps in the ATAC-seq protocol that, based on our experience, have the greatest impact on data quality when adapting this method for emerging model organisms. Specifically, we discuss the importance of nuclei isolation, the incubation conditions of the Tn5 transposase, and PCR amplification of the library. Furthermore, we outline essential quality checkpoints during the bioinformatic analysis of ATAC-seq data to assist in assessing data integrity and consistency. Given that many emerging model organisms may not be readily available in laboratory cultures, we also emphasize the importance of evaluating how different preservation methods affect ATAC-seq data quality. Based on examples in one spider and one ant species, we demonstrate that replication and thorough quality controls at all steps of the protocol and data analysis are essential to assess the usability of ATAC-seq data. Our data highlights the importance of isolating the right number of intact nuclei, as well as ensuring optimal amplification conditions during library preparation to obtain good-quality sequence data for downstream analyses. We recommend using fresh tissue samples if possible because we show that direct cryopreservation of the tissue may affect chromatin integrity. This effect could be avoided or reduced by preserving the homogenate in cell culture medium. Overall, we explain the ATAC-seq protocol and downstream analyses in detail and give step-by-step advice to researchers who are new to the field and want to implement this method. With careful planning and validation, ATAC-seq can reveal the regulatory landscape of a genome and aid in identifying elements that govern gene expression.

Animals↗

PubMed2025

A platform supporting generation and isolation of random transposon mutants in Chlamydia trachomatis.

Chlamydia species represent a paradigm for understanding successful obligate intracellular parasitism. Despite limited genetic malleability, development of genetic tools has facilitated the elucidation of molecular mechanisms governing infectivity. Random mutagenesis approaches provide one of the most powerful strategies available to accomplish untargeted elucidation of gene function. Unfortunately, initial progress in transposon-mediated mutagenesis of Chlamydia has been challenging. To increase efficiency, we developed a plasmid-based system that couples conditional plasmid maintenance with a previously described strategy leveraging inducible expression of the Himar1-derived C9 transposase. Our pOri-Tn(Q) construct was maintained in Chlamydia trachomatis cultivated with antibiotics but was rapidly cured in the absence of antibiotic selection. pOri-Tn(Q) supported transposition events when transposase expression was induced during infection. Induction was accompanied by loss of the plasmid backbone when penicillin G was used to select for only the transposable element. C9 induction during iterative passaging was used to increase the overall insertion frequency and accumulate an expanded pool of transposon mutants. The approach supported isolation of individual mutant strains from the mixed pool, and whole-genome sequencing confirmed that the recovered strains harbored single insertions.IMPORTANCEChlamydia trachomatis is a prevalent human pathogen exerting a tremendous negative impact on human health. A complete understanding of how these bacteria create and maintain an intracellular niche and avoid/subvert host defense mechanisms to cause disease is lacking. The utility of transposon-mediated, random mutagenesis in supporting forward genetic studies is well established in a multitude of genetically tractable systems. This study reports the development of a plasmid-based system capable of generating mutant pools and supporting subsequent isolation of individual transposon mutants. This step is an important advance in providing a mechanism capable of supporting downstream studies interrogating chlamydial biology.

Chlamydia trachomatis↗

PubMed1979

DNA sequence analysis of the transposon Tn3: three genes and three sites involved in transposition of Tn3.

The complete nucleotide sequence of the transposon Tn3 and of 20 mutations which affect its transposition are reported. The mutations, generated in vitro by random insertion of synthetic restriction sites, proved to contain small duplications or deletions immediately adjacent to the new restriction site. By determining the phenotype and DNA sequence of these mutations we were able to generate an overlapping phenotypic and nucleotide map. This 4957 bp transposon encodes three polypeptides which account for all but 350 bp of its total coding capacity. These proteins are the transposase, a high molecular weight polypeptide (1015 amino acids) encoded by the tnpA gene; the Tn3-specific repressor, a low molecular weight polypeptide (185 amino acids) encoded by the tnpR gene; and the 286 amino acid beta-lactamase. The 38 bp inverted repeats flanking Tn3 appear to be absolutely required in cis for Tn3 to transpose. Genetic data suggest that Tn3 contains a third site (Gill et al., 1978), designated IRS (internal resolution site), whose absence results in the insertion of two complete copies of Tn3 as direct repeats into the recipient DNA. We suggest that these direct repeats of complete copies of Tn3 are intermediates in transposition, and that the IRS site is required for recombination and subsequent segregation of the direct repeats to leave a single copy of Tn3 (Gill et al., 1978). A 23 nucleotide sequence within the amino terminus of the transposase which shares strong sequence homology with the inverted repeat may be the internal resolution site.

Base Sequence↗

PubMed2026

Programmable enzymes for targeted gene insertion.

Genome editing technologies have advanced from nuclease-based reagents that generate programmed DNA double-strand breaks, which can cause deleterious effects, to next-generation reagents that perform controlled DNA modification through double-strand break-independent mechanisms, such as base editing and prime editing. Although these approaches enable precise small-scale sequence changes, methods for programmable insertion of large DNA cargos have been limited. The ability to write entire genes or large regions into the genome could transform the treatment of genetically heterogeneous disorders, for which numerous pathogenic variants underlie a common disease and mutation-specific editing strategies are impractical. Recent advances in computational genome mining have accelerated the discovery of naturally occurring enzymes with novel biochemical and functional properties, including recombinases and transposases capable of large-scale modifications. Moreover, directed evolution, rational engineering and expanded homologue discovery are enabling the repurposing and optimization of these systems for genome engineering. Here we review recent technology development efforts that harness diverse enzymes for kilobase-scale genome engineering, with a particular focus on CRISPR-associated transposase systems.

Journal Article↗

PubMed2025

PATTY corrects open chromatin bias for improved bulk and single-cell CUT&Tag profiling.

Precise profiling of epigenomes is essential for better understanding chromatin biology and gene regulation. Cleavage Under Targets & Tagmentation (CUT&Tag) is an efficient epigenomic profiling technique that can be performed on a low number of cells and at the single-cell level. With its growing adoption, CUT&Tag datasets spanning diverse biological systems are rapidly accumulating in the field. CUT&Tag assays use the hyperactive transposase Tn5 for DNA tagmentation. Tn5's preference toward accessible chromatin alters CUT&Tag sequence read distributions in the genome and introduces open chromatin bias that can confound downstream analysis, an issue more substantial in sparse single-cell data. We show that open chromatin bias extensively exists in published CUT&Tag datasets, including those generated with recently optimized high-salt protocols. To address this challenge, we present PATTY (Propensity Analyzer for Tn5 Transposase Yielded bias), a comprehensive computational method that corrects open chromatin bias in CUT&Tag data by leveraging accompanying ATAC-seq. By integrating transcriptomic and epigenomic data using machine learning and integrative modeling, we demonstrate that PATTY enables accurate and robust detection of occupancy sites for both active and repressive histone modifications, including H3K27ac, H3K27me3, and H3K9me3, with experimental validation. We further develop a single-cell CUT&Tag analysis framework built on PATTY and show improved cell clustering when using bias-corrected single-cell CUT&Tag data compared to using uncorrected data. Beyond CUT&Tag, PATTY sets a foundation for further development of bias correction methods for improving data analysis for all Tn5-based high-throughput assays.

Journal Article↗

PubMed2025

PATTY corrects open-chromatin bias for improved bulk and single-cell CUT&Tag profiling.

Precise profiling of epigenomes is essential for better understanding chromatin biology and gene regulation. Cleavage Under Targets & Tagmentation (CUT&Tag) is an efficient epigenomic profiling technique that can be performed on a low number of cells and at the single-cell level. With its growing adoption, CUT&Tag datasets spanning diverse biological systems are rapidly accumulating in the field. CUT&Tag assays use the hyperactive transposase Tn5 for DNA tagmentation. Tn5's preference toward accessible chromatin alters CUT&Tag sequence read distributions in the genome and introduces open-chromatin bias that can confound downstream analysis, an issue more substantial in sparse single-cell data. We show that open-chromatin bias extensively exists in published CUT&Tag datasets, including those generated with recently optimized high-salt protocols. To address this challenge, we present PATTY (Propensity Analyzer for Tn5 Transposase Yielded bias), a comprehensive computational method that corrects open-chromatin bias in CUT&Tag data by leveraging accompanying ATAC-seq. By integrating transcriptomic and epigenomic data using machine learning and integrative modeling, we demonstrate that PATTY enables accurate and robust detection of occupancy sites for both active and repressive histone modifications, including H3K27ac, H3K27me3, and H3K9me3, with experimental validation. We further develop a single-cell CUT&Tag analysis framework built on PATTY and show improved cell clustering when using bias-corrected single-cell CUT&Tag data compared to using uncorrected data. Beyond CUT&Tag, PATTY sets a foundation for further development of bias correction methods for improving data analysis for all Tn5-based high-throughput assays.

Journal Article↗

PubMed2026

Evidence for dual pathways of Tc1/mariner domestication in Drosophila.

BACKGROUND: The domestication of transposable elements is a key source of evolutionary innovation, yet the pathways by which their functional modules are repurposed by the host remain poorly understood. The Tc1/mariner superfamily is a widespread group of DNA transposons, but the prevalence and patterns of their domestication are underexplored. RESULTS: We performed a systematic genomic screen across 43 drosophilid species using stringent criteria for molecular domestication. This analysis identified five high-confidence, evolutionarily conserved genes derived from Tc1/mariner transposases. Phylogenetic and structural analyses suggest domestication via two distinct molecular pathways: co-option of the DNA-binding module and co-option of the catalytic domain. The DNA-binding module pathway includes CG4570, the previously known genes cag and toy (the latter fused with a homeodomain), and a lineage-restricted gene in the Drosophila obscura group that exhibits signatures of recent domestication. In contrast, the catalytic domain pathway is represented solely by CG14478. Structural modeling reveals that CG14478 protein preserves a canonical DDE endonuclease fold. Co-expression network analysis suggests potential cellular roles of these genes: CG14478 is linked to RNA/chromatin-related processes, CG4570 to cell cycle/chromosome functions, cag to ciliary and nuclear functions, and toy to neuronal development. CONCLUSIONS: This study establishes a stringent framework for identifying domesticated TEs, demonstrating that Tc1/mariner elements are co-opted via two distinct pathways: retention of either catalytic or DNA-binding modules. Our findings suggest that domestication is a dynamic continuum, ranging from recent, lineage-specific events to ancient, conserved genes, and underscore how genomic conflict with TEs can drive eukaryotic evolution and regulatory complexity.

Animals↗

PubMed2025

ATAC-seq for Characterizing Host and Pathogen Genome Accessibility During Virus Infection.

Chromatin regulation provides a mechanism through which cells dynamically and rapidly regulate their gene expression profiles, playing a pivotal role in diverse biological processes and disease states. The Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) is a method that enables genome-wide detection of accessible chromatin regions, providing information on nucleosome positioning and the epigenetic regulation of the chromatin structure. ATAC-seq has been used in various biological contexts, and several reports have demonstrated its application to studying infections with viral or bacterial pathogens. The ability to characterize changes in viral or bacterial genome accessibility during infections provides insights into both pathogen replication and host defense mechanisms. Viral genomes undergo dynamic changes in their structural landscape to facilitate replication and evade host immune responses. Additionally, host cells encode DNA sensors, which are specialized proteins that bind to viral genomes to initiate innate immune responses and sometimes, to suppress viral gene expression. ATAC-seq enables the systematic detection of key structural changes on the viral genome mediated by either viral or host proteins, offering mechanistic insights into virus-host interactions. Here, we describe an ATAC-seq method optimized for studying changes in chromatin accessibility in both host and viral genomes. We have previously applied this method to demonstrate a systematic decrease in the genome accessibility of herpes simplex virus type I (HSV-1) enabled by a host antiviral factor, the interferon-gamma inducible protein 16 (IFI16) during infection of human fibroblasts. This protocol can be adapted to various biological contexts involving the introduction of foreign DNA, making it a valuable tool for a broad range of research endeavors.

Humans↗

PubMed2025

Capturing Chromatin Organization by MNase-seq and ATAC-seq.

Hox genes play a pivotal role during development. Their expression is tightly controlled in a spatiotemporal manner, ensuring that specific body structures develop at the correct locations and times during development. Various genomics approaches have been used to capture temporal and dynamic regulation of Hox gene expression at the nucleosome/chromatin level. This chapter focuses on the utilization of capture MNase-seq and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq), two advanced techniques that enable the exploration of chromatin accessibility and nucleosome positioning within these critical genomic regions.

Chromatin↗

PubMed2026

Generation of germline-transmitting transgenic sheep by piggyBac-mediated transgenesis using pronuclear and cytoplasmic gene injection approaches.

Sheep represent an important large-animal model for biomedical research and biopharmaceutical production. Although the piggyBac transposon system offers efficient and stable genomic integration, the optimal gene delivery strategy for ovine embryos remains unclear. This study evaluated piggyBac-mediated transgenesis using pronuclear injection (PNI) in both in vivo- and in vitro-derived embryos and assessed cytoplasmic injection (CTI) as an alternative approach. In vivo-derived embryos were obtained from superovulated Kıvırcık ewes approximately 40 h after gonadotropin-releasing hormone administration, whereas in vitro-derived embryos were produced from slaughterhouse-derived oocytes. All embryos were injected with the hyperactive piggyBac transposase-based pmhyGENIE-3 construct (10 ng/µL). In vivo-derived embryos were transferred immediately after injection, whereas in vitro-derived embryos were cultured for 3 days and screened for EGFP expression prior to transfer. Among 65 in vitro-derived embryos injected by PNI, no transgenic offspring was obtained. In contrast, PNI of 19 in vivo-derived embryos resulted in one transgenic lamb (5.3%). CTI of 12 in vivo-derived embryos similarly produced one transgenic lamb (8.3%). Whole-genome sequencing of the healthy founder male produced by CTI identified a single detectable genomic integration locus on chromosome 10 within a non-coding RNA locus (LOC121820439). Germline transmission was confirmed by in vitro fertilization using sperm from the founder male, with EGFP expression detected in 10.1% (10/99) resulting embryos. These findings provide proof-of-concept evidence for piggyBac-mediated transgenesis in sheep and support the feasibility of cytoplasmic injection as an alternative gene-delivery approach under the conditions tested.

Animals↗

PubMed2025

Integration of therapeutic cargo into the human genome with programmable type V-K CAST.

CRISPR-associated (Cas) transposases (CAST) are RNA-guided systems capable of programmable integration of large segments of DNA without creating double-strand breaks. Engineered Cascade CAST function in human cells but are challenging to deploy due to the complexity of the targeting components. Unlike Cascade, which require three Cas proteins, type V-K CAST require a single Cas12k effector for targeting. Here, we show that compact type V-K CAST from uncultivated microbes are repurposable for programmable DNA integration into the genome of human cells. Engineering for nuclear localization and function enables integration of a therapeutically relevant transgene at a safe-harbor site in multiple human cell types. Notably, off-targets are rare events reproducibly found in specific genomic regions. These CAST advancements are expected to accelerate applications of genome editing to therapeutic development, biotechnology, and synthetic biology.

Humans↗

PubMed2025

A hierarchical, count-based model highlights challenges in scATAC-seq data analysis and points to opportunities to extract finer-resolution information.

BACKGROUND: Data from Single-cell Assay for Transposase Accessible Chromatin with Sequencing (scATAC-seq) is highly sparse. While current computational methods feature a range of transformation procedures to extract meaningful information, major challenges remain. RESULTS: Here, we discuss the major scATAC-seq data analysis challenges such as sequencing depth normalization and region-specific biases. We present a hierarchical count model that is motivated by the data generating process of scATAC-seq data. Our simulations show that current scATAC-seq data, while clearly containing physical single-cell resolution, are too sparse to infer true informational-level single-cell, single-region of chromatin accessibility states. CONCLUSIONS: While the broad utility of scATAC-seq at a cell type level is undeniable, describing it as fully resolving chromatin accessibility at single-cell resolution, particularly at individual locus level, may overstate the level of detail currently achievable. We conclude that chromatin accessibility profiling at true single-cell, single-region resolution is challenging with current data sensitivity, but that it may be achieved with promising developments in optimizing the efficiency of scATAC-seq assays.

Single-Cell Analysis↗

PubMed2026

Clonotypic characterization defines B-cell drivers of clonal expansion and intratumor heterogeneity in IgM monoclonal gammopathies.

Waldenström macroglobulinemia (WM) and IgM monoclonal gammopathy of undetermined significance (MGUS) share the same cell of origin but differ in clonal size. Compared with other B-cell neoplasms, the lymphoplasmacytic clone in WM can be rather small, limiting our understanding of clonal expansion. We applied an integrative approach using single-cell RNA with B-cell receptor (BCR) sequencing, the assay for transposase-accessible chromatin, and whole-genome sequencing to characterize the tumor clone in patients with IgM MGUS, smoldering WM (SWM), and symptomatic WM (WM). IgM MGUS and low- or intermediate-risk SWM harbored multiple B-cell clones compared to WM. CD9, JCHAIN, RASSF6, and DUSP22 were the main markers of the dominant B-cell clone at gene expression and chromatin activity levels, with CD9 preferentially expressed in plasma cell-like tumor cells. POU2F2 had high activity in the tumor clone and was linked to CD9 regulatory regions. MYD88 and IGLL5 mutations, mainly associated with the mutational signature SBS5, were present in minor clones, whereas the MYD88 mutation was also detected in nonexpanded B-cells. The 6q deletion was present in tumor cells from high-risk patients, which harbored fitness advantage over copy-neutral tumor cells. Coding mutations clustered tumor and minor clones from oligoclonal patients and were associated with abnormal transcriptional programs. The B-cell clones also showed enriched predicted interactions with monocytes. Our integrative single-cell approach reveals the importance of clone size in IgM gammopathy and identifies key markers promoting clonal expansion.

Journal Article↗

PubMed2025

Integrated Multiomics Analyses of the Molecular Landscape of Sarcopenia in Alcohol-Related Liver Disease.

BACKGROUND: Skeletal muscle is a major target for ethanol-induced perturbations, leading to sarcopenia in alcohol-related liver disease (ALD). The complex interactions and pathways involved in adaptive and maladaptive responses to ethanol in skeletal muscle are not well understood. Unlike hypothesis-driven experiments, an integrated multiomics-experimental validation approach provides a comprehensive view of these interactions. METHODS: We performed multiomics analyses with experimental validation to identify novel regulatory mechanisms of sarcopenia in ALD. Studies were done in a comprehensive array of models including ethanol-treated (ET) murine and human-induced pluripotent stem cell-derived myotubes (hiPSCm), skeletal muscle from a mouse model of ALD (mALD) and human patients with alcohol-related cirrhosis and controls. We generated 13 untargeted datasets, including chromatin accessibility (assay for transposase accessible chromatin), RNA sequencing, proteomics, phosphoproteomics, acetylomics and metabolomics, and conducted integrated multiomics analyses using UpSet plots and feature extraction. Key findings were validated using immunoblots, redox measurements (NAD+/NADH ratio), imaging and senescence-associated molecular phenotype (SAMP) assays. Mechanistic studies included mitochondrial-targeted Lactobacillus brevis NADH oxidase (MitoLbNOX) to increase redox ratio and MitoTempo as a mitochondrial free radical scavenger. RESULTS: Multiomics analyses revealed enrichment in mitochondrial oxidative function, protein synthesis and senescence pathways consistent with the known effects of hypoxia-inducible factor 1α (HIF1α) during normoxia. Across preclinical and clinical models, HIF1α targets (n = 32 genes) and signalling genes (n > 100 genes) (n = 3 ATACseq, n = 65 phosphoproteomics, n = 10 acetylomics, n = 6 C2C12 proteomics, n = 106 C2C12 RNAseq, n = 64 hiPSC RNAseq, n = 30 hiPSC proteomics, n = 3 mouse proteomics, n = 25 mouse RNAseq, n = 8 human RNAseq, n = 3 human proteomics) were increased. Stabilization of HIF1α (C2C12, 6hEtOH 0.24 ± 0.09; p = 0.043; mALD 0.32 ± 0.074; p = 0.005; data shown as mean difference ± standard error mean) was accompanied by enrichment in the early transient and late change clusters, -log(p-value) = 1.5-3.8, of the HIF1α signalling pathway. Redox ratio was reduced in ET myotubes (C2C12: 15512 ± 872.1, p < 0.001) and mALD muscle, with decreased expression of electron transport chain components (CI-V, p < 0.05) and Sirt3 (C2C12: 0.067 ± 0.023, p = 0.025; mALD: 0.41 ± 0.12, p = 0.013). Acetylation of mitochondrial proteins was increased in both models (C2C12: 107364 ± 4558, p = 0.03; mALD: 40036 ± 18 987, p = 0.049). Ethanol-induced SAMP was observed across models (P16: C2C12: 0.2845 ± 0.1145, p < 0.05; hiPSCm: 0.2591, p = 0.041). MitoLbNOX treatment reversed redox imbalance, HIF1α stabilization, global acetylation and myostatin expression (p < 0.05). CONCLUSIONS: An integrated multiomics approach, combined with experimental validation, identifies HIF1α stabilization and accelerated post-mitotic senescence as novel mechanisms of sarcopenia in ALD. These findings show the complex molecular interactions leading to mitochondrial dysfunction and progressive sarcopenia in ALD.

Sarcopenia↗

PubMed2026

Fate of antibiotic resistance genes during rural domestic wastewater treatment: Anaerobic unit as enrichment hotspot versus aerobic unit as attenuation zone.

Rural domestic wastewater treatment systems are important but understudied reservoirs for antibiotic resistance genes (ARGs), whose full-process migration mechanisms remain unclear. Herein, the contribution of each treatment unit of ARGs was investigated using metagenomic methods across two seasons in typical rural domestic wastewater treatment systems. Although a removal efficiency (69 % in winter and 22 % in summer) was observed for ARGs, higher antibiotic residues and temperature dramatically induced ARG occurrence in wastewater and horizontal gene transfer (HGT) risk during wastewater treatment. The ARG abundances in the anaerobic unit increased by 1.6-2.1 fold compared to the regulating pool, primarily driven by elevated mobile genetic element (MGE) activity. In sharp contrast, ARG reduction was achieved through ARG host removal and suppressed HGT potential in the aerobic unit. Notably, mobile ARGs were dominated by tetracycline resistance genes in winter and co-dominated by tetracycline and sulfonamide genes in summer, with most flanked by transposases. Key pathogenic hosts, including Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa carrying ARG-MGE complexes, were primarily concentrated in the regulating pool and the influent, forming high-risk upstream sources of dissemination. Partial least-squares path model highlighted MGEs as the primary drivers, and variance partitioning analysis indicated that MGEs account for 31 % of the explained variation in ARGs during wastewater treatment. In summary, the anaerobic unit was an ARG enrichment hotspot, while the aerobic unit as ARG attenuation zone during wastewater treatment. These findings provide crucial evidence to optimize rural wastewater treatment processes and to target the control of antibiotic resistance.

Wastewater↗

PubMed2026

Single-cell mapping of regulatory DNA-protein interactions.

Gene expression is controlled by transcription factors (TFs), whose genome binding is shaped by chromatin accessibility and histone modifications, yet mapping these interactions, particularly those with weak affinity or a transient nature, in single cells remains technically challenging. To address this gap, we developed docking and deamination followed by sequencing (D&D-seq), a single-cell immuno-tethering technology for profiling DNA-protein interactions. D&D-seq couples an antibody-binding nanobody to a cytosine base editor, a combination that enables detection of weak or transient factor binding through targeted cytosine-to-uracil editing at protein-bound genomic sites. This approach is compatible with standard single-cell multi-omic workflows and therefore allows integrated analyses of gene regulation. Using assay for transposase-accessible chromatin using sequencing (ATAC-seq) and single-cell ATAC-seq (scATAC-seq), we assessed chromatin accessibility as a functional readout of TF activity, and by coupling D&D-seq with whole-genome sequencing, we captured CTCF binding in both active and inactive chromatin compartments.

Animals↗