Project description:Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) associated protein 13a (Cas13a) has been described as a superior tool to short-interfering (si) RNAs for specific gene silencing by targeting RNAs through Watson-Crick binding of the target and activation of nuclease activity. However, we observed that activation of LwaCas13a in mammalian HEK293T cells leads to unspecific targeting RNAs, which led to cell toxicity and death.
Project description:CRISPR-Cas13 systems have recently been employed to silence RNAs in yeast, plants, mammalian cell lines and animals, however, collateral effects induced by Cas13 may impede their research and therapeutic applications. Here, we found Cas13a and CasRx-mediated RNA knockdown induced substantial collateral effects on both exogenous and endogenous genes in mammalian cells. Moreover, transgenic mice carrying CasRx, with or without targeting guide RNA, exhibited high lethality. Therefore, our results present limitations of CasRx, requiring a solution to address its fidelity before clinical applications.
Project description:CRISPR-Cas13 systems have been adapted as versatile toolkits for RNA-related applications. Here we systematically evaluate the performance of several prominent Cas13 family effectors (Cas13a, Cas13b and Cas13d) under lentiviral vectors and reveal surprisingly differential defects and characteristics of these systems. Using RNA immunoprecipitation sequencing, transcriptome profiling, biochemistry analysis and high-throughput CRISPR-Cas13 screening approaches, we determine that each Cas13 system has its intrinsic RNA targets in mammalian cells. Viral process-related host genes can be targeted by Cas13 and affect the production of fertile lentiviral particles, thereby restricting the utility of lentiviral Cas13 systems. Multiple RNase activities of Cas13 are involved in endogenous RNA targeting. Unlike target-induced collateral effect, intrinsic RNA targeting can be specific, target-independent and dynamically tuned by varied states of Cas13 nucleases. Our work not only provides guidance to appropriately utilize lentiviral Cas13 systems, but also raises cautions about intrinsic RNA targeting during Cas13-based basic and therapeutic applications.
Project description:CRISPR-Cas13 systems have been adapted as versatile toolkits for RNA-related applications. Here we systematically evaluate the performance of several prominent Cas13 family effectors (Cas13a, Cas13b and Cas13d) under lentiviral vectors and reveal surprisingly differential defects and characteristics of these systems. Using RNA immunoprecipitation sequencing, transcriptome profiling, biochemistry analysis and high-throughput CRISPR-Cas13 screening approaches, we determine that each Cas13 system has its intrinsic RNA targets in mammalian cells. Viral process-related host genes can be targeted by Cas13 and affect the production of fertile lentiviral particles, thereby restricting the utility of lentiviral Cas13 systems. Multiple RNase activities of Cas13 are involved in endogenous RNA targeting. Unlike target-induced collateral effect, intrinsic RNA targeting can be specific, target-independent and dynamically tuned by varied states of Cas13 nucleases. Our work not only provides guidance to appropriately utilize lentiviral Cas13 systems, but also raises cautions about intrinsic RNA targeting during Cas13-based basic and therapeutic applications.
Project description:CRISPR-Cas13 systems have been adapted as versatile toolkits for RNA-related applications. Here we systematically evaluate the performance of several prominent Cas13 family effectors (Cas13a, Cas13b and Cas13d) under lentiviral vectors and reveal surprisingly differential defects and characteristics of these systems. Using RNA immunoprecipitation sequencing, transcriptome profiling, biochemistry analysis and high-throughput CRISPR-Cas13 screening approaches, we determine that each Cas13 system has its intrinsic RNA targets in mammalian cells. Viral process-related host genes can be targeted by Cas13 and affect the production of fertile lentiviral particles, thereby restricting the utility of lentiviral Cas13 systems. Multiple RNase activities of Cas13 are involved in endogenous RNA targeting. Unlike target-induced collateral effect, intrinsic RNA targeting can be specific, target-independent and dynamically tuned by varied states of Cas13 nucleases. Our work not only provides guidance to appropriately utilize lentiviral Cas13 systems, but also raises cautions about intrinsic RNA targeting during Cas13-based basic and therapeutic applications.
Project description:In this study we analyzed the effects of an altered Cas13a expression in vivo, in presence or absence of ectopically expressed protospacer RNA (plasmid pCV2_SB6), by RNA-sequencing. The genomic modification of the cas13a controlling promoter enables altered expression of cas13a by adding either subinhibitory crystal violet (CV) concentrations (for transcriptional repression of cas13a), or additionally IPTG (for transcriptional induction of cas13a), to the mutant cultures. Transcriptome profiles were compared to corresponding wild type controls.
2024-04-29 | GSE255203 | GEO
Project description:Off-target profiling of CRISPR-Cas13a
Project description:We develop a CRISPR-Assisted RNA-Protein Interaction Detection method (CARPID), which leverages CRISPR/CasRx-based RNA targeting and proximity labeling to identify binding proteins of specific lncRNA in the native cellular context.