Ontology highlight
ABSTRACT:
PROVIDER: PRJNA802843 | ENA |
REPOSITORIES: ENA
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Project description:Prime editing enables the precise modification of genomes through reverse transcription of template sequences appended to the 3′ ends of CRISPR–Cas guide RNAs. To identify cellular determinants of prime editing, we developed scalable prime editing reporters and performed genome-scale CRISPR-interference screens. From these screens, a single factor emerged as the strongest mediator of prime editing: the small RNA-binding exonuclease protection factor La. Further investigation revealed that La promotes prime editing across approaches (PE2, PE3, PE4 and PE5), edit types (substitutions, insertions and deletions), endogenous loci and cell types but has no consistent effect on genome-editing approaches that rely on standard, unextended guide RNAs. Previous work has shown that La binds polyuridine tracts at the 3′ ends of RNA polymerase III transcripts. We found that La functionally interacts with the 3′ ends of polyuridylated prime editing guide RNAs (pegRNAs). Guided by these results, we developed a prime editor protein (PE7) fused to the RNA-binding, N-terminal domain of La. This editor improved prime editing with expressed pegRNAs and engineered pegRNAs (epegRNAs), as well as with synthetic pegRNAs optimized for La binding. Together, our results provide key insights into how prime editing components interact with the cellular environment and suggest general strategies for stabilizing exogenous small RNAs therein.
2024-01-22 | GSE253424 | GEO
Project description:A truncated reverse transcriptase enhances prime editing by split AAV vectors
| PRJNA846287 | ENA
Project description:Template switching by a group II intron reverse transcriptase: biochemical analysis and implications for RNA-seq
| PRJNA575026 | ENA
Project description:Prime editing is a highly versatile CRISPR-based genome editing technology with the potential to correct the vast majority of genetic defects1. However, correction of a disease phenotype in vivo in somatic tissues has not been achieved yet. Here, we establish proof-of-concept for in vivo prime editing, that resulted in rescue of a metabolic liver disease. We first develop a size-reduced prime editor (PE) lacking the RNaseH domain of the reverse transcriptase (SpCas9-PERnH), and a linker- and NLS-optimized intein-split PE construct (SpCas9-PE p.1153) for delivery by adeno-associated viruses (AAV). Systemic dual AAV-mediated delivery of this variant in neonatal mice enables installation of a transversion mutation at the Dnmt1 locus with 15% efficiency on average. Next, we targeted the disease-causing mutation in the phenylalanine hydroxylase (Pah)enu2 mouse model for phenylketonuria (PKU). Correction rates of 1.5% using the dual AAV approach could be increased to up to 14% by delivery of full-length SpCas9-PE via adenoviral vector 5 (AdV5), leading to full restoration of physiological blood phenylalanine (L-Phe) levels below 120 µmol/L. Our study demonstrates in vivo prime editing in the liver at two independent loci, emphasizing the potential of PEs for future therapeutic applications.
2021-12-29 | GSE174757 | GEO
Project description:Telomerase is a specialized reverse transcriptase that uses an intrinsic RNA subunit as the template for telomeric DNA synthesis. Biogenesis of human telomerase requires its RNA subunit (hTR) to fold into a multi-domain architecture that includes the template-containing pseudoknot (t/PK) and the three-way junction (CR4/5). These two hTR domains bind the telomerase reverse transcriptase (hTERT) protein and are thus essential for telomerase catalytic activity. Here, we probe the structure of hTR in living cells using dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) and ensemble deconvolution analysis. Unexpectedly, approximately 15% of the steady state population of hTR has a CR4/5 conformation lacking features required for hTERT binding. Mutagenesis demonstrates that stabilization of the alternative CR4/5 conformation is detrimental to telomerase assembly and activity. We propose that this misfolded portion of the cellular hTR pool is either slowly refolded or degraded. Thus, kinetic traps for RNA folding that have been so well-studied in vitro may also present barriers for assembly of ribonucleoprotein complexes in vivo.
2023-10-20 | GSE245536 | GEO
Project description:Prime editing is a novel genome editing technology using fusion proteins of Cas9-nickase and reverse transcriptase, that holds promise to correct a wide variety of genetic defects.
We succeeded in efficient prime editing and functional recovery of disease-causing mutations in patient-derived liver and intestinal stem cell organoids. Whole genome sequencing of did not detect off-target mutations or a mutational signature induced by prime editing.
| EGAS00001004611 | EGA
Project description:Purpose: We are using the illumina sequencing to compare the false positive and true positive circular RNA findings to confine the method to detect the true circular RNAs Methods: The testis whole transcriptome profiling was generated from 4-week mouse testis using illumina Nextseq, duplicated. The sequence reads that passed quality filters were analyzed at the transcript isoform level with TopHat followed by Cufflinks. Results: our data suggest that circular RNAs identified based on junction sequences in the RNA-seq reads, especially those from Illumina Hiseq sequencing, mostly result from template-switching events during reverse transcription by MMLV-derived reverse transcriptases. It is critical to employ reverse transcriptases lacking terminal transferase activity (e.g., MonsterScript) to construct sequencing library or perform RT-PCR for identification and quantification of true circular RNAs. Conclusions: Our study represents the first detailed analysis of retinal transcriptomes, with biologic replicates, generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of expression profiles. Our results show that NGS offers a comprehensive and more accurate quantitative and qualitative evaluation of mRNA content within a cell or tissue. We conclude that RNA-seq based transcriptome characterization would expedite genetic network analyses and permit the dissection of complex biologic functions. The wild type mouse testis RNAs were constructed NGS library by two different enzyme, then parallel sequenced in illumina Nextseq
2016-07-05 | E-GEOD-83992 | biostudies-arrayexpress
Project description:Direct tracking of reverse-transcriptase speed and template sensitivity: implications for sequencing and analysis of long RNA molecules
| PRJNA802821 | ENA