Project description:The bacterial CRISPR-Cas9 system has been widely adapted for RNA-guided genome editing and gene regulation in diverse organisms yet its in vivo target specificity is poorly understood. Here we provide the first genome-wide binding maps of nuclease-deactivated Cas9 loaded with guide RNAs in mammalian cells. We find a 5-nucleotide seed region in the guide RNA targets Cas9 to thousands of sites in the genome. Chromatin accessibility limits binding to the other hundreds of thousands sites with matching seed sequences, and consequently 70% of off-target binding sites are associated with genes. U-rich seeds have low numbers of off-target sites limited by both low guide RNA abundance and scarcity of complimentary sites in accessible chromatin. Unexpectedly, off-target sites show little evidence of cleavage, supporting a two-state model reminiscent of eukaryotic RNAi machinery where a short seed match triggers binding but extensive pairing is required for cleavage. ChIP-seq of HA-dCas9 loaded with 4 sgRNAs (Phc1-sg1, Phc1-sg2, Nanog-sg2, and Nanog-sg3) in mouse, and 2 sgRNAs in human (EMX1-sg1 and EMX1-sg3)
Project description:Cells were transfected with plasmids containing AsCas12f variants and sgRNAs for gene-editing. Off-target effect was determined using GUIDE-seq on an Illumina Nextseq platform.
Project description:The clustered regularly interspaced short palindromic repeat (CRISPR)-associated enzyme Cas9 is an RNA-guided nuclease that has been widely adapted for genome editing in eukaryotic cells. However, the in vivo target specificity of Cas9 is poorly understood and most studies rely on in silico predictions to define the potential off-target editing spectrum. Using chromatin immunoprecipitation followed by sequencing (ChIP-seq), we delineate the genome-wide binding panorama of catalytically inactive Cas9 directed by two different single guide (sg) RNAs targeting the Trp53 locus. Cas9:sgRNA complexes are able to load onto multiple sites with short seed regions adjacent to 5’NGG3’ protospacer adjacent motifs (PAM). Examination of dmCas9 binding sites using two Trp53 targeting sgRNAs in Arf -/- MEF cell line (mouse).
Project description:tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing) is an RNA-mediated gene expression control technology that has therapeutic potential. This technology is based on the properties of tRNase ZL that it can cleave any target RNA at any desired site under the direction of an appropriate artificial small guide RNA (sgRNA) and that cytosolic tRNase ZL can modulate gene expression by cleaving mRNA under the direction of cellular 5M-bM-^@M-2-half-tRNA or microRNA as sgRNA. In order to estimate a number of potential therapeutic heptamer-type sgRNAs for hematological malignancies, we constructed an sgRNA library composed of 156 heptamer-type sgRNAs, and examined how the sgRNAs affect viability of leukemia and myeloma cells. And we found that 20 of the 156 sgRNAs can efficiently induce apoptosis in at least one of the cancer cell lines. Furthermore, we demonstrated that 4 of the 20 effective sgRNAs can reduce growth rates of HL60 cells in mouse xenograft models. DNA microarray analysis for changes in an mRNA profile by these four heptamer-type sgRNAs suggested at least one candidate target mRNA that contains a potential tRNase ZL target site for each sgRNA. Changes in gene expression in HL60 cells were measured after 18-hour incubation in the absence or presence of one of five different heptamer-type sgRNAs. *Heptamer sequences requested but not provided by submitter
Project description:We provide examples of the next-generation sequencing results obtained after analyzing sgRNAs (single guide RNAs) isolated from an input library and from parasites three passages after transfection.
Project description:Assess the on- and off-target effects of dox-inducible CRISPR/Cas9 and CRISPRi constructs in a human iPS cell line. Transcript quantification of 3 cell lines, each plus or minus doxycycline and with or without specific single guide RNAs (sgRNAs), with 2 biological replicates each.
Project description:RNA-seq was used to define the role of MAB21L4 in epidermal differentiation by first employing CRISPR/Cas9 to disrupt MAB21L4 with two independent single guide RNAs (sgRNAs) to create pools of MAB21L4-ablated primary human keratinocytes that were then placed onto human dermis and grown for three days at the air-liquid interface to generate organotypic skin tissue.
Project description:Technologies allowing for specific regulation of endogenous genes are valuable for the study of gene functions and have great potential in therapeutics. We created the CRISPR-on system, a two-component transcriptional activator consisting of a nuclease-dead Cas9 (dCas9) protein fused with a transcriptional activation domain and single guide RNAs (sgRNAs) with complementary sequence to gene promoters. We demonstrate that CRISPR-on can efficiently activate exogenous reporter genes in both human and mouse cells in a tunable manner. In addition, we show that robust reporter gene activation in vivo can be achieved by injecting the system components into mouse zygotes. Furthermore we show that CRISPR-on can activate the endogenous IL1RN, SOX2, and OCT4 genes. The most efficient gene activation was achieved by clusters of 3 to 4 sgRNAs binding to the proximal promoters suggesting their synergistic action in gene induction. Significantly, when sgRNAs targeting multiple genes were simultaneously introduced into cells, robust multiplexed endogenous gene activation was achieved. Genome-wide expression profiling demonstrated high specificity of the system. We used microarray to assay the gene expression changes after transfection of dCas9VP160 with the different sgRNAs
Project description:To explore the underlying molecular mechanisms of FOXO3A-regulated AML cell function To determine the impact of FOXO3A deficiency on AML cells, we generated knock-out (KO) cells of FOXO3A using small guide RNAs (sgRNAs)
Project description:RNA-seq was used to define the role of CACYBP in epidermal differentiation by first employing CRISPR/Cas9 to disrupt CACYBP with two independent single guide RNAs (sgRNAs) to create pools of CACYBP-ablated primary human keratinocytes that were immortalized with HPV E6/E7 and then placed onto human dermis and grown for three days at the air-liquid interface to generate organotypic skin tissue.