Scaffold RNA engineering in type V CRISPR-Cas systems: a potent way to enhance gene expression in the yeast Saccharomyces cerevisiae.
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE249355 | GEO | 2023/12/05
REPOSITORIES: GEO
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Project description:The CRISPR-Cas universe continues to expand. The type II CRISPR-Cas system from Streptococcus pyogenes (SpyCas9) is most widely used for genome editing due to its high efficiency in cells and organisms. However, concentrating on a single CRISPR-Cas system imposes limits on target selection and multiplexed genome engineering. We hypothesized that CRISPR-Cas systems originating from different bacterial species could operate simultaneously and independently due to their distinct single-guide RNAs (sgRNAs) or CRISPR-RNAs (crRNAs), and protospacer adjacent motifs (PAMs). Additionally, we hypothesized that CRISPR-Cas activity in zebrafish could be regulated through the expression of inhibitory anti-CRISPR (Acr) proteins. Here, we use a simple mutagenesis approach to demonstrate that CRISPR-Cas systems from Streptococcus pyogenes (SpyCas9), Streptococcus aureus (SauCas9), Lachnospiraceae bacterium (LbaCas12a, previously known as LbCpf1), Acidaminococcus sp. (AspCas12a, previously known as AsCpf1) and Neisseria meningitidis (Nme2Cas9) are orthogonal systems capable of operating simultaneously in zebrafish. We implemented multichannel CRISPR recording using up to three CRISPR systems, and show that LbaCas12a may provide superior information density compared to previous methods. We also demonstrate that type II Acrs (anti-CRISPRs) are effective inhibitors of SpyCas9 in zebrafish. These results indicate that at least five CRISPR-Cas systems and two anti-CRISPR proteins are functional in zebrafish embryos. These orthogonal CRISPR-Cas systems and Acr proteins will enable combinatorial and intersectional strategies for spatiotemporal control of genome editing and genetic recording in animals.
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Project description:Synthetic transcription factors can be applied in many areas of biotechnology, medicine, and basic research. In contrast to current methods based on engineering new DNA-binding proteins, we show that Cas9 fused to a transcriptional activation domain can be targeted by combinations of guide RNA molecules to induce the expression of endogenous human genes. This simple approach for targeted gene activation circumvents the need for engineering new proteins and will enable widespread synthetic gene regulation. HEK293T cells were transfected with plasmid expressing Cas9-VP64 fusion protein and a guide RNA. As a control, empty guide RNA was transfected. Gene expression was then measured using mRNA-seq, and differential expression calculated using DESeq. All experiments were performed in biological duplicates or triplicates.
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Project description:The development of CRISPR-Cas systems for targeting DNA and RNA in diverse organisms has transformed biotechnology and biological research. Moreover, the CRISPR revolution has highlighted bacterial adaptive immune systems as a rich and largely unexplored frontier for discovery of new genome engineering technologies. In particular, the class 2 CRISPR-Cas systems, which use single RNA-guided DNA-targeting nucleases such as Cas9, have been widely applied for targeting DNA sequences in eukaryotic genomes. Here, we report DNA-targeting and transcriptional control with class I CRISPR-Cas systems. Specifically, we repurpose the effector complex from type I variants of class 1 CRISPR-Cas systems, the most prevalent CRISPR loci in nature, that target DNA via a multi-component RNA-guided complex termed Cascade. We validate Cascade expression, complex formation, and nuclear localization in human cells and demonstrate programmable CRISPR RNA (crRNA)-mediated targeting of specific loci in the human genome. By tethering transactivation domains to Cascade, we modulate the expression of targeted chromosomal genes in both human cells and plants. This study expands the toolbox for engineering eukaryotic genomes and establishes Cascade as a novel CRISPR-based technology for targeted eukaryotic gene regulation.
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Project description:The development of CRISPR-Cas systems for targeting DNA and RNA in diverse organisms has transformed biotechnology and biological research. Moreover, the CRISPR revolution has highlighted bacterial adaptive immune systems as a rich and largely unexplored frontier for discovery of new genome engineering technologies. In particular, the class 2 CRISPR-Cas systems, which use single RNA-guided DNA-targeting nucleases such as Cas9, have been widely applied for targeting DNA sequences in eukaryotic genomes. Here, we report DNA-targeting and transcriptional control with class I CRISPR-Cas systems. Specifically, we repurpose the effector complex from type I variants of class 1 CRISPR-Cas systems, the most prevalent CRISPR loci in nature, that target DNA via a multi-component RNA-guided complex termed Cascade. We validate Cascade expression, complex formation, and nuclear localization in human cells and demonstrate programmable CRISPR RNA (crRNA)-mediated targeting of specific loci in the human genome. By tethering transactivation domains to Cascade, we modulate the expression of targeted chromosomal genes in both human cells and plants. This study expands the toolbox for engineering eukaryotic genomes and establishes Cascade as a novel CRISPR-based technology for targeted eukaryotic gene regulation.
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Project description:Synthetic DNA-binding proteins have found broad application in gene therapies and as tools for interrogating biology. Engineered proteins based on the CRISPR/Cas9 and TALE systems have been used to alter genomic DNA sequences, control transcription of endogenous genes, and modify epigenetic states. Although the activity of these proteins at their intended genomic target sites have been assessed, the genome-wide effects of their action have not been extensively characterized. Additionally, the role of chromatin structure in determining the binding of CRISPR/Cas9 and TALE proteins to their target sites and the regulation of nearby genes is poorly understood. Characterization of the activity these proteins using modern high-throughput genomic methods would provide valuable insight into the specificity and off-target effects of CRISPR- and TALE-based genome engineering tools. We have analyzed the genome-wide effects of TALE- and CRISPR-based transcriptional activators targeted to the promoters of two different endogenous human genes in HEK293T cells using a variety of high-throughput DNA sequencing methods. In particular, we assayed the DNA-binding specificity of these proteins and their effects on the epigenome. DNA-binding specificity was evaluated by ChIP-seq and RNA-seq was used to measure the specificity of these activators in perturbing the transcriptome. Additionally, DNase-seq was used to identify the chromatin state at target sites of the synthetic transcriptional activators and the genome-wide chromatin remodeling that occurs as a result of their action. Our results show that these genome engineering technologies are highly specific in both binding to their promoter target sites and inducing expression of downstream genes when multiple activators bind to a single promoter. Moreover, we show that these synthetic activators are able to induce the expression of silent genes in heterochromatic regions of the genome by opening regions of closed chromatin and decreasing DNA methylation. Interestingly, the transcriptional activation domain was not necessary for DNA-binding or chromatin remodeling in these regions, but was critical to inducing gene expression. This study shows that these CRISPR- and TALE-based transcriptional activators are exceptionally specific. Although we detected limited binding of off-target sites in the genome and changes to genome structure, these off-target event did not lead to any detectable changes in gene regulation. Collectively, these results underscore the potential for these technologies to make precise changes to gene expression for gene and cell therapies or fundamental studies of gene function. HEK293T cells were transfected in triplicate with plasmids expressing synthetic transcription factors. The synthetic TFs were either (a) dCas9-VP64 fusion protein and a targeting guide RNA (gRNA), or (b) a TALE-VP64 fusion protein engineered to bind to a specific target site in the genome. As a control, cells were transfected with plasmids expressing GFP. After transfection, ChIP-seq was used to identify both on-target and off-target binding sites for the synthetic TFs.
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Project description:Synthetic DNA-binding proteins have found broad application in gene therapies and as tools for interrogating biology. Engineered proteins based on the CRISPR/Cas9 and TALE systems have been used to alter genomic DNA sequences, control transcription of endogenous genes, and modify epigenetic states. Although the activity of these proteins at their intended genomic target sites have been assessed, the genome-wide effects of their action have not been extensively characterized. Additionally, the role of chromatin structure in determining the binding of CRISPR/Cas9 and TALE proteins to their target sites and the regulation of nearby genes is poorly understood. Characterization of the activity these proteins using modern high-throughput genomic methods would provide valuable insight into the specificity and off-target effects of CRISPR- and TALE-based genome engineering tools. We have analyzed the genome-wide effects of TALE- and CRISPR-based transcriptional activators targeted to the promoters of two different endogenous human genes in HEK293T cells using a variety of high-throughput DNA sequencing methods. In particular, we assayed the DNA-binding specificity of these proteins and their effects on the epigenome. DNA-binding specificity was evaluated by ChIP-seq and RNA-seq was used to measure the specificity of these activators in perturbing the transcriptome. Additionally, DNase-seq was used to identify the chromatin state at target sites of the synthetic transcriptional activators and the genome-wide chromatin remodeling that occurs as a result of their action. Our results show that these genome engineering technologies are highly specific in both binding to their promoter target sites and inducing expression of downstream genes when multiple activators bind to a single promoter. Moreover, we show that these synthetic activators are able to induce the expression of silent genes in heterochromatic regions of the genome by opening regions of closed chromatin and decreasing DNA methylation. Interestingly, the transcriptional activation domain was not necessary for DNA-binding or chromatin remodeling in these regions, but was critical to inducing gene expression. This study shows that these CRISPR- and TALE-based transcriptional activators are exceptionally specific. Although we detected limited binding of off-target sites in the genome and changes to genome structure, these off-target event did not lead to any detectable changes in gene regulation. Collectively, these results underscore the potential for these technologies to make precise changes to gene expression for gene and cell therapies or fundamental studies of gene function. HEK293T cells were transfected in triplicate with plasmids expressing synthetic transcription factors. The synthetic TFs were either (a) dCas9-VP64 fusion protein and a targeting guide RNA (gRNA), or (b) a TALE-VP64 fusion protein engineered to bind to a specific target site in the genome. As a control, cells were transfected with plasmids expressing GFP. After transfection, RNA-seq was used to identify both on-target and off-target binding sites for the synthetic TFs. The data in this submission were generated using the TALE transfection experiments.
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