Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1028567 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR26395951_1.fastq.gz | Fastqsanger.gz | |||
| SRR26395951_2.fastq.gz | Fastqsanger.gz | |||
| SRR26395952_1.fastq.gz | Fastqsanger.gz | |||
| SRR26395952_2.fastq.gz | Fastqsanger.gz | |||
| SRR26395953_1.fastq.gz | Fastqsanger.gz |
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Project description:As the ancestor of CRISPR-Cas12 nucleases, TnpB represents the most compact gene editing tool currently available. Recent studies have identified multiple TnpB systems with gene editing activity in mammalian cells, and the potential of TnpB in treating diseases has been demonstrated in animal models. However, the editing characteristics of various TnpB systems, comparable to CRISPR tools, require more extensive investigation. Using a standardized evaluation framework, we conducted a thorough analysis of the editing properties of four TnpB variants alongside representative Cas12 and Cas9 tools. Overall, TnpBs exhibit intermediate editing activity and safety profiles among all tested systems, with ISYmu1 TnpB demonstrating a good performance in both editing activity and specificity. Considering its compact size, potent editing efficiency and high specificity, ISYmu1 TnpB represents a promising candidate for in vivo gene therapy applications.
2025-01-01 | GSE264389 | GEO
Project description:Insertion sequences (IS) are compact and pervasive transposable elements found in bacteria, which encode only the genes necessary for their mobilization and maintenance. IS200/IS605 elements undergo ‘peel-and-paste’ transposition catalyzed by a TnpA transposase, but intriguingly, they also encode diverse, TnpB-family genes that are evolutionarily related to the CRISPR-associated effectors Cas9 and Cas12. Recent studies demonstrated that TnpB-family enzymes function as RNA-guided DNA endonucleases, but the broader biological role of this activity has remained enigmatic. Here we show that IscB and TnpB are essential to prevent loss of the donor IS element and potential transposon extinction as a consequence of the TnpA transposition mechanism. We first performed phylogenetic analysis of IscB/TnpB proteins and selected a family of related IS elements from Geobacillus stearothermophilus that we predicted would be mobilized by a common TnpA homolog. After reconstituting transposition using a heterologous expression system in E. coli, we found that IS elements were readily lost from the donor site due to the activity of TnpA in rejoining the flanking sequences back together upon excision. However, these IS elements also encode non-coding RNAs that guide TnpB and IscB nucleases to precisely recognize and cleave these excision products, leading either to elimination of the excision product or re-installation of the transposon through recombination. Indeed, under experimental conditions in which TnpA and TnpB-RNA complexes were co-expressed together with a genomically integrated IS element, transposon retention was significantly increased relative to conditions expressing TnpA alone. Remarkably, both TnpA and TnpB recognize the same AT-rich transposon-adjacent motif (TAM) during transposon excision and RNA-guided DNA cleavage, respectively, revealing a striking convergence in the evolution of DNA sequence specificity between transposase and nuclease. Collectively, our study reveals that RNA-guided DNA cleavage is a primal biochemical activity that arose to bias the selfish inheritance of transposable elements, which was later co-opted during the evolution of CRISPR-Cas adaptive immunity for antiviral defense.
2023-06-01 | GSE223127 | GEO
Project description:RNA-guided endonucleases form the crux of diverse biological processes and technologies, including adaptive immunity, transposition, and genome editing. Some of these enzymes are components of insertion sequences (IS) in the IS200/IS605 and IS607 transposon families. Both IS families encode a TnpA transposase and TnpB nuclease, an RNA-guided enzyme ancestral to CRISPR-Cas12. In eukaryotes and their viruses, TnpB homologs occur as two distinct types, Fanzor1 and Fanzor2. We analyzed the evolutionary relationships between prokaryotic TnpBs and eukaryotic Fanzors, revealing that a clade of IS607 TnpBs with unusual active site arrangement found primarily in cyanobacteria likely gave rise to both types of Fanzors. The widespread nature of Fanzors imply that the properties of this particular group of IS607 TnpBs were particularly suited to adaptation and evolution in eukaryotes and their viruses. Biochemical analysis of a prokaryotic IS607 TnpB and virally encoded Fanzor1s revealed features that may have fostered co-evolution between TnpBs/Fanzors and their cognate transposases. These results provide insight into the evolutionary origins of a ubiquitous family of RNA-guided proteins that shows remarkable conservation across the three domains of life.
2023-11-18 | GSE246134 | GEO
Project description:Temporally controlling cre recombinase through tamoxifen (TAM) induction has many advantages for biomedical research studies. While most projects use TAM induction of mice at early post-natal or adolescence (<2m.o.) ages, age-related neurodegeneration and aging studies can require experimental designs with cre induction in older mice (>12m.o.). While anecdotally reported to be problematic, there are no published comparisons of TAM mediated cre induction at young and older ages. Cx3cr1creERT2 mice for studying microglial were crossed to a floxed NuTRAP reporter to compare cre induction at young (3m.o.) and old (18m.o) ages. Specificity and efficiency microglial labeling was identical at 24m.o. in mice induced with TAM at 3m.o. or 18m.o. of age. Age-related microglial translatomic changes were nearly identical regardless of TAM induction age. While each cre and flox mouse line should be validated before use, these findings demonstrate that TAM induction of cres can be performed even into older mouse ages.
2023-12-14 | GSE241574 | GEO
Project description:Comprehensive assessment of activity, specificity, and safety of hypercompact TnpB systems for gene editing
| PRJNA1102325 | ENA
Project description:Transposon-encoded tnpB and iscB genes encode RNA-guided DNA nucleases that promote their own selfish spread through targeted DNA cleavage and homologous recombination. These widespread gene families were repeatedly domesticated over evolutionary timescales, leading to the emergence of diverse CRISPR-associated nucleases including Cas9 and Cas12. We set out to test the hypothesis that TnpB nucleases may have also been repurposed for novel, unexpected functions other than CRISPR-Cas. Here, using phylogenetics, structural predictions, comparative genomics, and functional assays, we uncover multiple instances of programmable transcription factors that we name TnpB-like nuclease-dead repressors (TldR). These proteins employ naturally occurring guide RNAs to specifically target conserved promoter regions of the genome, leading to potent gene repression in a mechanism akin to CRISPRi technologies invented by humans. Focusing on a TldR clade found broadly in Enterobacteriaceae, we discover that bacteriophages exploit the combined action of TldR and an adjacently encoded phage gene to alter the expression and composition of the host flagellar assembly, a transformation with the potential to impact motility, phage susceptibility, and host immunity. Collectively, this work showcases the diverse molecular innovations that were enabled through repeated exaptation of transposon-encoded genes, and reveals the evolutionary trajectory of diverse RNA-guided transcription factors.
2024-04-22 | GSE245749 | GEO
Project description:The proteins in an MCF-7 cell line were probed for tamoxifen (TAM) and n-desmethyl tamoxifen (NDT) induced stability changes using the Stability of Proteins from Rates of Oxidation (SPROX) technique in combination with two different quantitative proteomics strategies. Together the SILAC- and iTRAQ-SPROX experiments described here enabled over 1000 proteins to be assayed for TAM- and NDT- induced protein stability changes, and a total of 163 and 200 protein hits were identified in the TAM and NDT studies, respectively. A subset of high confidence hits were assessed for experimental links to the ER using a STRING analysis. TAM was shown to induce stabilization of Y-box binding protein 1 (YBX1), a protein recently shown to bind the estrogen receptor. TAM was shown to directly interact with purified recombinant YBX1 with Pulse Proteolysis (PP). These results support YBX1 as a direct protein target of TAM. Proteins with altered expression levels with TAM and NDT treatment were identified with SILAC quantitation. In total, 799 and 671 proteins were probed for TAM- and NDT- induced expression changes, respectively, and 49 and 30 proteins had altered expression. This work also involved the use of a novel data analysis strategy to identify protein targets of ligands using the SPROX technique.
2019-11-08 | PXD006747 | Pride
Project description:The proteins in an MCF-7 cell line were probed for tamoxifen (TAM) and n-desmethyl tamoxifen (NDT) induced stability changes using the Stability of Proteins from Rates of Oxidation (SPROX) technique in combination with two different quantitative proteomics strategies. Together the SILAC- and iTRAQ-SPROX experiments described here enabled over 1000 proteins to be assayed for TAM- and NDT- induced protein stability changes, and a total of 163 and 200 protein hits were identified in the TAM and NDT studies, respectively. A subset of high confidence hits were assessed for experimental links to the ER using a STRING analysis. TAM was shown to induce stabilization of Y-box binding protein 1 (YBX1), a protein recently shown to bind the estrogen receptor. TAM was shown to directly interact with purified recombinant YBX1 with Pulse Proteolysis (PP). These results support YBX1 as a direct protein target of TAM. Proteins with altered expression levels with TAM and NDT treatment were identified with SILAC quantitation. In total, 799 and 671 proteins were probed for TAM- and NDT- induced expression changes, respectively, and 49 and 30 proteins had altered expression. This work also involved the use of a novel data analysis strategy to identify protein targets of ligands using the SPROX technique.
2019-11-08 | PXD006732 | Pride
Project description:Transient abnormal myelopoiesis (TAM) is a clonal pre-leukemic disorder that progresses to myeloid leukemia of Down syndrome (ML-DS) through the accumulation of genetic alterations. To investigate the mechanism of leukemogenesis in this disorder, a xenograft model of TAM was established using NOD/Shi-scid, IL-2Rγnull mice. In serial transplantations, engrafted TAM-derived cells showed the emergence of divergent subclones with another GATA1 mutation and various CNAs, including a 16q deletion and 1q gain, which are clinically associated with ML-DS. These results suggest that genetically heterogeneous subclones with varying leukemia-initiating potential already exist in the neonatal TAM phase, and ML-DS may develop from a pool of such minor clones through clonal selection. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from murine bone marrow (hCD45 sorted) or human peripheral blood samples. Copy number analysis of Affymetrix 500K SNP arrays was performed for xenografted TAM samples of 3 patients. There are also 3 samples from TAM patients in remission, which were used as references for copy number inference.
2013-03-01 | E-GEOD-44739 | biostudies-arrayexpress