Ontology highlight
ABSTRACT:
PROVIDER: PRJNA590635 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Exploiting PAM diversity of LbCas12a variants to edit multiple oncogenic mutations
| PRJNA784339 | ENA
Project description:Nuclear receptors function as ligand-regulated transcription factors whose ability to regulate diverse physiological processes is closely linked with conformational changes induced upon ligand binding. Understanding how conformational populations of nuclear receptors are shifted by various ligands could illuminate strategies for the design of synthetic modulators to regulate specific transcriptional programs. Here, we investigate ligand-induced conformational changes using a reconstructed, ancestral nuclear receptor. By making substitutions at a key position, we engineer receptor variants with altered ligand specificities. We use atomistic molecular dynamics (MD) simulations with enhanced sampling to generate ensembles of wildtype and engineered receptors in combination with multiple ligands, followed by conformational analysis and prediction of ligand activity. We combine cellular and biophysical experiments to allow correlation of MD-based predictions with functional ligand profiles, as well as elucidation of mechanisms underlying altered transcription in receptor variants. We determine that conformational ensembles accurately predict ligand responses based on observed population shifts, even within engineered receptors that were constitutively active or transcriptionally unresponsive in experiments. These studies provide a platform which will allow structural characterization of physiologically-relevant conformational ensembles, as well as provide the ability to design and predict transcriptional responses in novel ligands.
2022-10-12 | PXD036076 | Pride
Project description:A key limitation of the commonly-used CRISPR enzyme S. pyogenes Cas9 is the strict requirement of an NGG protospacer-adjacent motif (PAM) at the target site, which reduces the number of accessible genomic loci. This constraint can be limiting for genome editing applications that require precise Cas9 positioning. Recently, two Cas9 variants with a relaxed PAM requirement (NG) have been developed (xCas9 and Cas9-NG) but their activity has been measured at only a small number of endogenous sites. Here we devised a high-throughput Cas9 pooled competition screen to compare the performance of both PAM-flexible Cas9 variants and wild-type Cas9 at thousands of genomic loci and across 3 modalities (gene knock-out, transcriptional activation and suppression). We show that PAM flexibility comes at a substantial cost of decreased DNA targeting and cutting. Of the PAM-flexible variants, we found that Cas9-NG outperforms xCas9 regardless of genome engineering modality or PAM. Finally, we combined xCas9 mutations with those of Cas9-NG, creating a stronger transcriptional modulator than existing PAM-flexible Cas9 variants.
2020-01-26 | GSE143892 | GEO
Project description:Human somatic cells may contain up to seven members of the histone H1 family contributing to chromatin compaction and regulation of nuclear processes, apparently with certain subtype specificities. Previous studies in T47D breast cancer cells determined that H1 variants are distributed in a variant-specific manner throughout the genome, although only H1.2 and H1X endogenous variants were mapped. Now, we performed ChIP-seq of five endogenous H1 variants (H1.0, H1.2, H1.4, H1.5, H1X) in T47D cells.
2021-08-16 | GSE166645 | GEO
Project description:Plant biotechnology needs new methods that accelerate design-build-test-learn cycles to develop new gene editing reagents. We have established ITER (Iterative Testing of Editing Reagents) based on arrayed protoplast transfections and high-content imaging, allowing one optimization cycle –from design to results– within three weeks. We validated ITER in wheat and maize protoplasts using Cas9 cytosine and adenine base editors and used it to develop an optimized LbCas12a-ABE system. Sequential improvement of five components –NLS, crRNA, LbCas12a nuclease, adenine deaminase and linker– led to a systematic, stepwise increase in ABE activity at extrachromosomal GFP reporter (from 0.5% to 40%) and endogenous target sites. We confirmed the activity of LbCas12a-ABE in stable wheat transformants and leveraged these improvements to develop a highly mutagenic LbCas12a nuclease and a LbCas12a-CBE. Our data show that ITER is a sensitive, versatile, and high-throughput platform that can be harnessed to accelerate the development of genome editing technologies in plants.
2022-11-21 | GSE200450 | GEO
Project description:CRISPR-Cas transcriptional tools have been widely applied for programmable regulation of complex biological networks. In comparison to eukaryotic systems, bacterial CRISPR activation (CRISPRa) has stringent target site requirements for effective gene activation. While genes may not always have an NGG protospacer adjacent motif (PAM) at the appropriate position, PAM-flexible dCas9 variants can expand the range of targetable sites. Here we systematically evaluate a panel of PAM-flexible dCas9 variants for their ability to activate bacterial genes. We observe that dxCas9-NG provides a high dynamic range of gene activation for sites with NGN PAMs while dSpRY permits modest activity across almost any PAM. Similar trends were observed for heterologous and endogenous promoters. For all variants tested, improved PAM-flexibility comes with the tradeoff that CRISPRi-mediated gene repression becomes less effective. Weaker CRISPR interference (CRISPRi) gene repression can be partially rescued by expressing multiple sgRNAs to target many sites in the gene of interest. Our work provides a framework to choose the most effective dCas9 variant for a given set of gene targets, which will further expand the utility of CRISPRa/i gene regulation in bacterial systems.
2022-11-15 | GSE217559 | GEO
Project description:we characterized a novel compact Cas12a ortholog, EbCas12a, from the Erysipelotrichia bacterium with activities in mammalian cells. It is with the PAM sequence of 5’-TTTV-3’ (V=A, G, C) and the smallest size of ~3.47kb among reported Cas12a orthologs so far. Moreover, enhanced EbCas12a (enEbCas12a) was also developed to have comparable editing efficiency with higher specificity to AsCas12a and LbCas12a in mammalian cells. With the help of the compact enEbCas12a, all-in-one AAV delivery system with crRNA for Cas12a was developed for both in vitro and in vivo. Altogether, with the help of the novel smallest high fidelity enEbCas12a, this first case of the all-in-one AAV delivery for Cas12a could greatly boost future gene therapy and scientific research.
2023-07-10 | GSE236647 | GEO
Project description:PamcKO/cKO mice, with loxp sites flanking exons previously deleted in the global Pam knockout, were created, viable and equivalent to wildtype mice in every test. Eliminating Pam expression in excitatory forebrain neurons reduced anxiety-like behavior, increased locomotor responsiveness to cocaine and improved thermoregulation in the cold. Eliminating Pam expression in cardiomyocytes increased anxiety-like behavior, improved thermoregulation and markedly diminished atrial levels of pro-atrial natriuretic peptide. RNASeq analysis of atria revealed a set of PAM-regulated transcripts related to cardiac function.
2019-08-13 | GSE132180 | GEO