Ontology highlight
ABSTRACT:
PROVIDER: PRJNA744264 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Combinatorial mutagenesis en masse optimizes the genome editing activities of SpCas9.
| PRJEB32521 | ENA
Project description:RNA-guided nucleases (RGNs) based on CRISPR systems permit installing short and large edits within eukaryotic genomes. However, precise genome editing is often hindered due to nuclease off- target activities and the multiple-copy character of the vast majority of chromosomal sequences. Dual nicking RGNs and high-specificity RGNs both exhibit low off-target activities. Here, we report that high-specificity Cas9 nucleases are convertible into nicking Cas9D10A variants whose precision is superior to that of the commonly used Cas9D10A nickase. Dual nicking RGNs based on a selected group of these Cas9D10A variants can yield gene knockouts and gene knock-ins at frequencies similar to or higher than those achieved by their conventional counterparts. Moreover, high-specificity dual nicking RGNs are capable of distinguishing highly similar sequences by “tiptoeing” over pre-existing single base-pair polymorphisms. Finally, high-specificity RNA-guided nicking complexes generally preserve genomic integrity, as demonstrated by unbiased genome-wide high-throughput sequencing assays. Thus, in addition to substantially enlarging the Cas9 nickase toolkit, we demonstrate the feasibility in expanding the range and precision of genome editing procedures. The herein introduced tools and multi-tier high-specificity genome editing strategies might be particularly beneficial whenever predictability and/or safety of genetic manipulations are paramount.
2020-12-08 | GSE153471 | GEO
Project description:The discovery that enhancers are regulated transcription units, encoding eRNAs, has raised new questions about the mechanisms of their activation. Here, we report an unexpected molecular mechanism that underlies ligand-dependent enhancer activation, based on DNA nicking to relieve torsional stress from eRNA synthesis. Using dihydrotestosterone (DHT)-induced binding of androgen receptor (AR) to prostate cancer cell enhancers as a model, we show rapid recruitment, within minutes, of DNA topoisomerase I (TOP1) to a large cohort of AR-regulated enhancers. Furthermore, we show that the DNA nicking activity of TOP1 is a prerequisite for robust eRNA synthesis and enhancer activation and is kinetically accompanied by the recruitment of ATR and the MRN complex, followed by additional components of DNA damage repair machinery to the AR-regulated enhancers. Together, our studies reveal a linkage between eRNA synthesis and ligand-dependent TOP1-mediated nicking - a strategy exerting quantitative effects on eRNA expression in regulating AR-bound enhancer-dependent transcriptional programs. Genome-wide binding analysis of AR, TOP1, MRE11 in prostate cancer cell line LNCaP with or without 5alpha-dihydrotestosterone (DHT) treatment. Nascent RNA analysis by global nuclear run-on (GRO-seq) in LNCaP cells transfected with siRNA with or without DHT treatment. Distribution of transcriptionally engaged RNA Pol II in LNCaP cells with or without DHT treatment by precision nuclear run-on and sequencing (PRO-seq).
2015-01-22 | E-GEOD-63202 | biostudies-arrayexpress
Project description:The discovery that enhancers are regulated transcription units, encoding eRNAs, has raised new questions about the mechanisms of their activation. Here, we report an unexpected molecular mechanism that underlies ligand-dependent enhancer activation, based on DNA nicking to relieve torsional stress from eRNA synthesis. Using dihydrotestosterone (DHT)-induced binding of androgen receptor (AR) to prostate cancer cell enhancers as a model, we show rapid recruitment, within minutes, of DNA topoisomerase I (TOP1) to a large cohort of AR-regulated enhancers. Furthermore, we show that the DNA nicking activity of TOP1 is a prerequisite for robust eRNA synthesis and enhancer activation and is kinetically accompanied by the recruitment of ATR and the MRN complex, followed by additional components of DNA damage repair machinery to the AR-regulated enhancers. Together, our studies reveal a linkage between eRNA synthesis and ligand-dependent TOP1-mediated nicking - a strategy exerting quantitative effects on eRNA expression in regulating AR-bound enhancer-dependent transcriptional programs.
2015-01-22 | GSE63202 | GEO
Project description:The CRISPR-Cas9 system enables efficient sequence-specific mutagenesis for creating germline mutants of model organisms. Key constraints in vivo remain the expression and delivery of active Cas9-guideRNA ribonucleoprotein complexes (RNPs) with minimal toxicity, variable mutagenesis efficiencies depending on targeting sequence, and high mutation mosaicism. Here, we established in vitro-assembled, fluorescent Cas9-sgRNA RNPs in stabilizing salt solution to achieve maximal mutagenesis efficiency in zebrafish embryos. Sequence analysis of targeted loci in individual embryos reveals highly efficient bi-allelic mutagenesis that reaches saturation at several tested gene loci. Such virtually complete mutagenesis reveals preliminary loss-of-function phenotypes for candidate genes in somatic mutant embryos for subsequent generation of stable germline mutants. We further show efficient targeting of functional non-coding elements in gene-regulatory regions using saturating mutagenesis towards uncovering functional control elements in transgenic reporters and endogenous genes. Our results suggest that in vitro assembled, fluorescent Cas9-sgRNA RNPs provide a rapid reverse-genetics tool for direct and scalable loss-of-function studies beyond zebrafish applications.
2016-05-01 | E-MTAB-4143 | biostudies-arrayexpress
Project description:This experiment aims at analyzing crossover distribution genome-wise, in the fission yeast. S. pombe strains PR109 (h- leu1-32 ura4-D18) and PR110 (h+ leu1-32 ura4-D18) were used for three successive rounds of mutagenesis with Ethylmethane Sulfonate Mutagenesis. Five independent clones of the first round of mutagenesis were at the root of two subsequent similar rounds of mutagenesis. Each clone used was checked for its ability to mate and sporulate. Eventually, five mutagenized clones from each of the PR109 and PR110 backgrounds were sequenced to identify de novo mutations and determine the optimal combinations of mutation patterns for recombination analyses.
2023-03-03 | E-MTAB-12514 | biostudies-arrayexpress
Project description:Clonal cellular variance often confounds reproducibility of forward and reverse genetic studies. We developed combinatorial approaches for whole genome saturated mutagenesis using haploid murine ES cells to permit induction and reversion of genetic mutations. Using these systems, we created a biobank with over 100000 individual ES cell lines with repairable and genetically bar coded mutations targeting 16950 genes. This biobank termed “Haplobank” is freely available. In addition, we developed a genetic color coding system for rapid repair of mutations and direct functional validation in sister clones. Using this system, we report functional validation of essential ES cell genes. We also identified phospholipase16G as a key pathway for cytotoxicity of human rhinoviruses, the most frequent cause of the common cold. Moreover, we derived 3D blood vessel organoids from haploid ES cells, combining conditional mutagenesis in haploid ES cells with tissue engineering. We identified multiple novel genes, such as Connexin43/Gja1, in blood vessel formation and tip cell specification in vitro and also in vivo. Taken together, we develop a conditional homozygous ES cell resource for the community to empower controlled genetic studies in murine ES cells and tissues derived from it.
2017-09-05 | GSE84089 | GEO
Project description:This experiment aims at analyzing crossover distribution genome-wise, in the fission yeast. S. pombe strains PR109 (h- leu1-32 ura4-D18) and PR110 (h+ leu1-32 ura4-D18) were used for three successive rounds of mutagenesis with Ethylmethane Sulfonate Mutagenesis. Five independent clones of the first round of mutagenesis were at the root of two subsequent similar rounds of mutagenesis. Each clone used was checked for its ability to mate and sporulate. Eventually, five mutagenized clones from each of the PR109 and PR110 backgrounds were sequenced to identify de novo mutations and determine the optimal combinations of mutation patterns for recombination analyses. The following h- x h+ crosses were selected and the corresponding tetrads dissected: BLP49 (A) x BLP23 (I), 29 tetrads; BLP59 (C) x BLP19 (H), 30 tetrads and BLP64 (D) x BLP33 (K), 33 tetrads.
2023-03-03 | E-MTAB-12516 | biostudies-arrayexpress