Project description:This study investigates the RNA targets and cleavage sites of endogenous Cas9 in the food-borne pathogen Campylobacter jejuni. Direct RNA binding targets of Cas9 in C. jejuni strain NCTC11168 were determined using RIP-seq. The Cleavage sites were then predicted in the RNA targets by comparing total transcriptome data from WT and deletion (cas9, crRNA3, tracrRNA, CRISPR-tracrRNA) strains. PAMs for the CjeCas9 were enriched using the PAM-SCANR platform, which operates through a GFP reporter gene. Upon GFP (and thus functional PAM) enrichment, fluorescing cells were isolated using FACS and prepared plasmid DNA was amplified and prepared for sequencing.
Project description:In this study the RNA targetome of the endonuclease Cas9, the trans-activating crRNA (tracrRNA) and a CRISPR-associated small RNA (scaRNA/NMnc0040) was determined in Neisseria meninigitidis serogroup C strain 8013 by RNA-seq.
Project description:CCM3 regulates blood-brain-barrier integrity and vascular maturation in vivo. CCM3 loss-of-function variants predispose to cerebral cavernous malformations (CCM). Various signalling pathways are deregulated upon CCM3 depletion in endothelial cells (ECs). In this study, we established a crRNA:tracrRNA:Cas9 RNP approach to efficiently knockout CCM3 in human ECs and studied the molecular and functional effects of its long-term inactivation. Using small RNA sequencing, we show that CCM3 regulates the expression of aging‑associated miRNAs.
Project description:Off-target (OT) analysis of different guide RNAs targeting PKLR gene. GUIDE-Seq analyses were done in HEK293 cells stably expressing Cas9 transfected with gRNA complexes, generated using Alt-R® CRISPR-Cas9 crRNA XT and Alt-R®CRISPR-Cas9 tracrRNA, and transfected with a dsODN tag
2021-04-13 | GSE171935 | GEO
Project description:Cas9-independent tracrRNA cytotoxicity in Lacticaseibacillus paracasei
| PRJNA1214207 | ENA
Project description:Bacterial long tracrRNA mediated genome editing in plant
Project description:Prokaryotes create adaptive immune memories by acquiring foreign DNA snippets, known as spacers, into the CRISPR array1. In type II CRISPR-Cas systems, the RNA-guided effector Cas9 also assists the acquisition machinery by selecting spacers from protospacer adjacent motif (PAM)-flanked DNA2,3. Here, we uncover the first biological role for Cas9 that is independent of its dual RNA partners. Following depletion of crRNA and/or tracrRNA, Neisseria apoCas9 stimulates spacer acquisition efficiency. Physiologically, Cas9 senses low levels of crRNA in cells with short CRISPR arrays – such as those undergoing array neogenesis or natural array contractions – and dynamically upregulates acquisition to quickly expand the small immune memory banks. As the CRISPR array expands, rising crRNA abundance in turn reduces apoCas9 availability, thereby dampening acquisition to mitigate autoimmunity risks associate with elevated acquisition. While apoCas9’s nuclease lobe alone suffices for stimulating acquisition, only full-length Cas9 responses to crRNA levels to boost acquisition in cells with low immunity depth. Finally, we show that this activity is evolutionarily conserved across multiple type II-C Cas9 orthologs. Altogether, we establish an auto-replenishing feedback mechanism in which apoCas9 safeguards CRISPR immunity depth by acting as both a crRNA sensor and a regulator of spacer acquisition.
Project description:This SuperSeries is composed of the following subset Series: GSE30622: Dual Role of FoxA1 in Androgen Receptor Binding to Chromatin, Androgen Signaling and Prostate Cancer [Expression Array] GSE30623: Dual Role of FoxA1 in Androgen Receptor Binding to Chromatin, Androgen Signaling and Prostate Cancer [ChIP_seq, DHS_seq] Refer to individual Series
Project description:The current commonly used single-guide RNA (sgRNA) structure has a shortened duplex compared with the native bacterial clustered regularly interspaced short palindromic repeats RNA (crRNA)–transactivating crRNA (tracrRNA) duplex. Here we show that modifying the sgRNA structure by extending the duplex length and mutating the fourth T of the continuous sequence of Ts (which is the pause signal for RNA polymerase III [pol III]) to C or G significantly, and sometimes dramatically, improves knockout efficiency in cells. In addition, the new sgRNA structure also significantly increases the efficiency of more challenging genome-editing procedures, such as gene deletion, which is important for inducing a loss-of-function in non-coding genes.