Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a tumor-selective one, targeted insertion of a prototypic CAR with either a selectable marker or an immunomodulatory receptor into a TCR locus or a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile and safe framework for orthogonal editing, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:The parallel disruption of multiple genes coupled with targeted transgene insertion offers a powerful strategy for more effective and precise cell engineering. However, such orthogonal editing involves the induction of multiple DNA breaks, raising safety concerns related to the risks of chromosomal translocations. Here, we present a polyfunctional CRISPR-Cas9-based strategy that enables both transgene insertion and epigenetic silencing at distinct genomic loci in a single treatment without inducing reciprocal chromosomal translocations. This is accomplished through an optimized all-in-one epigenome editor equipped with a catalytically active Cas9, whose endonuclease activity is selectively disabled at epigenetically silenced loci by the use truncated gRNAs. As a proof of concept, we demonstrated that this platform enables efficient multi-locus editing, including functional replacement of the endogenous TCR with a selectable retargeting cassette, targeting a prototypic CAR and an immunomodulatory receptor into a ubiquitously expressed gene, and durable, multiplexed epigenetic silencing of clinically relevant genes in primary human T cells. Polyfunctional editing establishes a versatile framework for orthogonal editing with an enhanced safety profile, broadening the scope of genome and epigenome engineering in cancer immunotherapy and beyond.
Project description:Chromosomal rearrangements including large DNA-fragment inversions, deletions, and duplications by Cas9 with paired sgRNAs are important to investigate structural genome variations and developmental gene regulation, but little is known about the underlying mechanism. Here we report that disrupting CtIP or FANCD2, which is thought to function in NHEJ, enhances precise DNA-fragment deletion. In addition, by analyzing the inserted nucleotides at the junctions of DNA-fragment deletions, inversions, duplications, and characterizing the cleaved products, we find that Cas9 endonucleolytically cleaves the noncomplementary strand with a flexible scissile profile upstream of -3 position of the PAM site in vivo and in vitro, generating overhanged DSB ends. Moreover, we find that engineered Cas9 nucleases have distinct cleavage profiles. Finally, Cas9-mediated nucleotide insertions are nonrandom and are equal to the combined sequences upstream of both PAM sites with predicted frequencies. Thus, precise and predictable DNA-fragment editing could be achieved by perturbing DNA repair genes and using appropriate PAM configurations. These findings have important implications regarding 3D chromatin folding and enhancer insulation during gene regulation.