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:CRISPR/Cas systems have gained prominence as powerful tools for genome engineering. Recent investigations into the crucial role of transposable elements (TEs) have stimulated research interest in manipulating TEs to elucidate their functions. Nevertheless, designing single guide RNAs (sgRNAs) that are both specific and efficient for TE manipulation presents a formidable challenge, considering the repetitive nature and high copy numbers of TEs. Although various sgRNA design tools have been developed for gene editing, an optimized sgRNA designer explicitly for TE manipulation has yet to be established. To bridge this gap, we presented CRISPR-TE, a web-based application featuring an accessible graphical user interface, available at https://www.crisprte.cn. CRISPR-TE could identify all potential sgRNAs for TEs and offers a comprehensive solution for efficient TE targeting at both the single duplicate and subfamily levels. We also demonstrated that young TEs can be targeted with higher coverage at the subfamily level. Finally, we validated the overexpression of SVAD, a human-specific TE, using dCas9-VP64 activator incorporated with three sgRNAs designed by our tool. Collectively, our findings suggest that CRISPR-TE may serve as a versatile framework for designing sgRNAs aimed at TE targeting.
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:The CRISPR-Cas9 system enables efficient sequence-specific mutagenesis for creating germline mutants of model organisms. Key constraints in vivo remain the expression and delivery of active Cas9-guideRNA ribonucleoprotein complexes (RNPs) with minimal toxicity, variable mutagenesis efficiencies depending on targeting sequence, and high mutation mosaicism. Here, we established in vitro-assembled, fluorescent Cas9-sgRNA RNPs in stabilizing salt solution to achieve maximal mutagenesis efficiency in zebrafish embryos. Sequence analysis of targeted loci in individual embryos reveals highly efficient bi-allelic mutagenesis that reaches saturation at several tested gene loci. Such virtually complete mutagenesis reveals preliminary loss-of-function phenotypes for candidate genes in somatic mutant embryos for subsequent generation of stable germline mutants. We further show efficient targeting of functional non-coding elements in gene-regulatory regions using saturating mutagenesis towards uncovering functional control elements in transgenic reporters and endogenous genes. Our results suggest that in vitro assembled, fluorescent Cas9-sgRNA RNPs provide a rapid reverse-genetics tool for direct and scalable loss-of-function studies beyond zebrafish applications.
Project description:To study the effect of genes that interface inflammatory and metabolic signaling, CRISPR/Cas9 has been used to delete CD5L and RORA in THP-1 human monocytic cell line. Cells transduced with sgRNAs targeting Renilla luciferase gene were used as controls. Deletion and control lines were differentiated with PMA and allowed to rest for 24 hours prior to isolation of total RNA.
Project description:Human acute myeloid leukemia cell lines OCI-AML2 and OCI-AML3 were used in a CRISPR/Cas9-mediated approach to specifically target DDX3X’s gene sequences encoding the RNA binding domain of the helicase. DDX3X RNA binding domain is bipartite in the two halves of the helicase core. sgRNAs were designed to target both halves of the domain (named RNA binding domain A and B – RBDA and RBDB). We performed RNA-seq to observe the gene expression changes in both OCI-AML2 and OCI-AML3 cell lines following the not-combined CRISPR/Cas9 –mediated targeting of both regions of the DDX3X RNA binding domain. Control CRISPR/Cas9 performed with no sgRNA expressing vector (named “empty vector”) was performed in both cell lines. The latter condition was used as a control for gene expression changes analysis, for each cell line.
Project description:Skeletal muscle satellite cells (SCs) are muscle stem cells responsible for muscle development and injury induced muscle regeneration. The pace of SC related study, however, is constrained partially by the technological limitations in generating genetically modified mice. Although the ease of use of CRISPR-Cas9 in genome manipulation has been documented in many cell lines and various species, its application in endogenous SCs remains elusive. In this study, we generated muscle-specific Cas9-expressing mice and achieved robust in vivo genome editing in juvenile SCs at the postnatal stage through AAV9 mediated short guide RNAs (sgRNAs) delivery. We also found adult quiescent SCs are reluctant to CRISPR/Cas9 editing despite efficient AAV9 transduction. To edit juvenile SCs in vivo, as a proof-of-concept, we delivered sgRNAs targeting MyoD, a key gene critical for muscle physiology and showed an efficient editing at MyoD locus, resulting in accumulation of SCs and defects in SCs differentiation which resembled the phenotypes reported in MyoD knockout mice. Further application of this system on potential key transcription factors (TFs) involved in SC fate transition, Myc, Bcl6 and Pknox2, unveiled their distinct functions in the early stage of SC activation and injury induced muscle regeneration. In addition, we revealed that Myc orchestrated SCs activation through impinging on 3D chromatin architecture. Altogether we established a robust muscle restricted CRISPR/Cas9-based gene editing platform in endogenous SCs and elucidated the functionality of key factors governing SC activities.
Project description:Skeletal muscle satellite cells (SCs) are muscle stem cells responsible for muscle development and injury induced muscle regeneration. The pace of SC related study, however, is constrained partially by the technological limitations in generating genetically modified mice. Although the ease of use of CRISPR-Cas9 in genome manipulation has been documented in many cell lines and various species, its application in endogenous SCs remains elusive. In this study, we generated muscle-specific Cas9-expressing mice and achieved robust in vivo genome editing in juvenile SCs at the postnatal stage through AAV9 mediated short guide RNAs (sgRNAs) delivery. We also found adult quiescent SCs are reluctant to CRISPR/Cas9 editing despite efficient AAV9 transduction. To edit juvenile SCs in vivo, as a proof-of-concept, we delivered sgRNAs targeting MyoD, a key gene critical for muscle physiology and showed an efficient editing at MyoD locus, resulting in accumulation of SCs and defects in SCs differentiation which resembled the phenotypes reported in MyoD knockout mice. Further application of this system on potential key transcription factors (TFs) involved in SC fate transition, Myc, Bcl6 and Pknox2, unveiled their distinct functions in the early stage of SC activation and injury induced muscle regeneration. In addition, we revealed that Myc orchestrated SCs activation through impinging on 3D chromatin architecture. Altogether we established a robust muscle restricted CRISPR/Cas9-based gene editing platform in endogenous SCs and elucidated the functionality of key factors governing SC activities.
Project description:Skeletal muscle satellite cells (SCs) are muscle stem cells responsible for muscle development and injury induced muscle regeneration. The pace of SC related study, however, is constrained partially by the technological limitations in generating genetically modified mice. Although the ease of use of CRISPR-Cas9 in genome manipulation has been documented in many cell lines and various species, its application in endogenous SCs remains elusive. In this study, we generated muscle-specific Cas9-expressing mice and achieved robust in vivo genome editing in juvenile SCs at the postnatal stage through AAV9 mediated short guide RNAs (sgRNAs) delivery. We also found adult quiescent SCs are reluctant to CRISPR/Cas9 editing despite efficient AAV9 transduction. To edit juvenile SCs in vivo, as a proof-of-concept, we delivered sgRNAs targeting MyoD, a key gene critical for muscle physiology and showed an efficient editing at MyoD locus, resulting in accumulation of SCs and defects in SCs differentiation which resembled the phenotypes reported in MyoD knockout mice. Further application of this system on potential key transcription factors (TFs) involved in SC fate transition, Myc, Bcl6 and Pknox2, unveiled their distinct functions in the early stage of SC activation and injury induced muscle regeneration. In addition, we revealed that Myc orchestrated SCs activation through impinging on 3D chromatin architecture. Altogether we established a robust muscle restricted CRISPR/Cas9-based gene editing platform in endogenous SCs and elucidated the functionality of key factors governing SC activities.
Project description:Skeletal muscle satellite cells (SCs) are muscle stem cells responsible for muscle development and injury induced muscle regeneration. The pace of SC related study, however, is constrained partially by the technological limitations in generating genetically modified mice. Although the ease of use of CRISPR-Cas9 in genome manipulation has been documented in many cell lines and various species, its application in endogenous SCs remains elusive. In this study, we generated muscle-specific Cas9-expressing mice and achieved robust in vivo genome editing in juvenile SCs at the postnatal stage through AAV9 mediated short guide RNAs (sgRNAs) delivery. We also found adult quiescent SCs are reluctant to CRISPR/Cas9 editing despite efficient AAV9 transduction. To edit juvenile SCs in vivo, as a proof-of-concept, we delivered sgRNAs targeting MyoD, a key gene critical for muscle physiology and showed an efficient editing at MyoD locus, resulting in accumulation of SCs and defects in SCs differentiation which resembled the phenotypes reported in MyoD knockout mice. Further application of this system on potential key transcription factors (TFs) involved in SC fate transition, Myc, Bcl6 and Pknox2, unveiled their distinct functions in the early stage of SC activation and injury induced muscle regeneration. In addition, we revealed that Myc orchestrated SCs activation through impinging on 3D chromatin architecture. Altogether we established a robust muscle restricted CRISPR/Cas9-based gene editing platform in endogenous SCs and elucidated the functionality of key factors governing SC activities.