| 1. |
- Heckl, Dirk, et al.
(författare)
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Toward whole-transcriptome editing with CRISPR-Cas9
- 2015
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Ingår i: Molecular Cell. - : Cell Press. - 1097-2765 .- 1097-4164. ; 58:4, s. 560-562
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Targeted regulation of gene expression holds huge promise for biomedical research. In a series of recent publications (Gilbert et al., 2014; Konermann et al., 2015; Zalatan et al., 2015), sophisticated, multiplex-compatible transcriptional activator systems based on the CRISPR-Cas9 technology and genome-scale libraries advance the field toward whole-transcriptome control.
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| 2. |
- Labenski, Verena, et al.
(författare)
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Alpharetroviral self-inactivating vectors produced by a superinfection-resistant stable packaging cell line allow genetic modification of primary human T lymphocytes.
- 2016
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 97, s. 97-109
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Tidskriftsartikel (refereegranskat)abstract
- Primary human T lymphocytes represent an important cell population for adoptive immunotherapies, including chimeric-antigen and T-cell receptor applications, as they have the capability to eliminate non-self, virus-infected and tumor cells. Given the increasing numbers of clinical immunotherapy applications, the development of an optimal vector platform for genetic T lymphocyte engineering, which allows cost-effective high-quality vector productions, remains a critical goal. Alpharetroviral self-inactivating vectors (ARV) have several advantages compared to other vector platforms, including a more random genomic integration pattern and reduced likelihood for inducing aberrant splicing of integrated proviruses. We developed an ARV platform for the transduction of primary human T lymphocytes. We demonstrated functional transgene transfer using the clinically relevant herpes-simplex-virus thymidine kinase variant TK.007. Proof-of-concept of alpharetroviral-mediated T-lymphocyte engineering was shown in vitro and in a humanized transplantation model in vivo. Furthermore, we established a stable, human alpharetroviral packaging cell line in which we deleted the entry receptor (SLC1A5) for RD114/TR-pseudotyped ARVs to prevent superinfection and enhance genomic integrity of the packaging cell line and viral particles. We showed that superinfection can be entirely prevented, while maintaining high recombinant virus titers. Taken together, this resulted in an improved production platform representing an economic strategy for translating the promising features of ARVs for therapeutic T-lymphocyte engineering.
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| 3. |
- Labuhn, Maurice, et al.
(författare)
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Refined sgRNA efficacy prediction improves large- and small-scale CRISPR-Cas9 applications
- 2018
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 46:3, s. 1375-1385
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Tidskriftsartikel (refereegranskat)abstract
- Genome editing with the CRISPR-Cas9 system has enabled unprecedented efficacy for reverse genetics and gene correction approaches. While off-target effects have been successfully tackled, the effort to eliminate variability in sgRNA efficacies-which affect experimental sensitivity-is in its infancy. To address this issue, studies have analyzed the molecular features of highly active sgRNAs, but independent cross-validation is lacking. Utilizing fluorescent reporter knock-out assays with verification at selected endogenous loci, we experimentally quantified the target efficacies of 430 sgRNAs. Based on this dataset we tested the predictive value of five recently-established prediction algorithms. Our analysis revealed a moderate correlation (r = 0.04 to r = 0.20) between the predicted and measured activity of the sgRNAs, and modest concordance between the different algorithms. We uncovered a strong PAM-distal GC-content-dependent activity, which enabled the exclusion of inactive sgRNAs. By deriving nine additional predictive features we generated a linear model-based discrete system for the efficient selection (r = 0.4) of effective sgRNAs (CRISPRater). We proved our algorithms' efficacy on small and large external datasets, and provide a versatile combined on-and off-target sgRNA scanning platform. Altogether, our study highlights current issues and efforts in sgRNA efficacy prediction, and provides an easily-applicable discrete system for selecting efficient sgRNAs.
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| 4. |
- Puram, Rishi V, et al.
(författare)
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Core Circadian Clock Genes Regulate Leukemia Stem Cells in AML
- 2016
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 165:2, s. 16-303
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Tidskriftsartikel (refereegranskat)abstract
- Leukemia stem cells (LSCs) have the capacity to self-renew and propagate disease upon serial transplantation in animal models, and elimination of this cell population is required for curative therapies. Here, we describe a series of pooled, in vivo RNAi screens to identify essential transcription factors (TFs) in a murine model of acute myeloid leukemia (AML) with genetically and phenotypically defined LSCs. These screens reveal the heterodimeric, circadian rhythm TFs Clock and Bmal1 as genes required for the growth of AML cells in vitro and in vivo. Disruption of canonical circadian pathway components produces anti-leukemic effects, including impaired proliferation, enhanced myeloid differentiation, and depletion of LSCs. We find that both normal and malignant hematopoietic cells harbor an intact clock with robust circadian oscillations, and genetic knockout models reveal a leukemia-specific dependence on the pathway. Our findings establish a role for the core circadian clock genes in AML.
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| 5. |
- Reimer, Jana, et al.
(författare)
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CRISPR-Cas9-induced t(11;19)/MLL-ENL translocations initiate leukemia in human hematopoietic progenitor cells in vivo
- 2017
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 102:9, s. 1558-1566
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Tidskriftsartikel (refereegranskat)abstract
- Chromosomal translocations that generate oncogenic fusion proteins are causative for most pediatric leukemias and frequently affect the MLL/ KMT2A gene. In vivo modeling of bona fide chromosomal translocations in human hematopoietic stem and progenitor cells is challenging but essential to determine their actual leukemogenic potential. We therefore developed an advanced lentiviral CRISPR-Cas9 vector that efficiently transduced human CD34(+) hematopoietic stem and progenitor cells and induced the t(11; 19)/MLL-ENL translocation. Leveraging this system, we could demonstrate that hematopoietic stem and progenitor cells harboring the translocation showed only a transient clonal growth advantage in vitro. In contrast, t(11; 19)/MLL-ENL-harboring CD34(+) hematopoietic stem and progenitor cells not only showed longterm engraftment in primary immunodeficient recipients, but t(11; 19)/ MLL-ENL also served as a first hit to initiate a monocytic leukemia-like disease. Interestingly, secondary recipients developed acute lymphoblastic leukemia with incomplete penetrance. These findings indicate that environmental cues not only contribute to the disease phenotype, but also to t(11; 19)/ MLL-ENL-mediated oncogenic transformation itself. Thus, by investigating the true chromosomal t(11; 19) rearrangement in its natural genomic context, our study emphasizes the importance of environmental cues for the pathogenesis of pediatric leukemias, opening an avenue for novel treatment options.
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