Derek Jantz
Durham University
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Featured researches published by Derek Jantz.
Plant Journal | 2010
Huirong Gao; Jeff Smith; Meizhu Yang; Spencer Jones; Vesna Djukanovic; Michael Nicholson; Ande West; Dennis L. Bidney; S. Carl Falco; Derek Jantz; L. Alexander Lyznik
The liguleless locus (liguleless1) was chosen for demonstration of targeted mutagenesis in maize using an engineered endonuclease derived from the I-CreI homing endonuclease. A single-chain endonuclease, comprising a pair of I-CreI monomers fused into a single polypeptide, was designed to recognize a target sequence adjacent to the LIGULELESS1 (LG1) gene promoter. The endonuclease gene was delivered to maize cells by Agrobacterium-mediated transformation of immature embryos, and transgenic T(0) plants were screened for mutations introduced at the liguleless1 locus. We found mutations at the target locus in 3% of the T(0) plants, each of which was regenerated from independently selected callus. Plants that were monoallelic, biallelic and chimeric for mutations at the liguleless1 locus were found. Relatively short deletions (shortest 2 bp, longest 220 bp) were most frequently identified at the expected cut site, although short insertions were also detected at this site. We show that rational re-design of an endonuclease can produce a functional enzyme capable of introducing double-strand breaks at selected chromosomal loci. In combination with DNA repair mechanisms, the system produces targeted mutations with sufficient frequency that dedicated selection for such mutations is not required. Re-designed homing endonucleases are a useful molecular tool for introducing targeted mutations in a living organism, specifically a maize plant.
Plant Biotechnology Journal | 2013
Kathleen D'halluin; Chantal Vanderstraeten; Jolien Van Hulle; Joanna Rosolowska; Ilse Van Den Brande; Anouk Pennewaert; Kristel D'Hont; Martine Bossut; Derek Jantz; Rene Ruiter; Jean Broadhvest
Recent developments of tools for targeted genome modification have led to new concepts in how multiple traits can be combined. Targeted genome modification is based on the use of nucleases with tailor-made specificities to introduce a DNA double-strand break (DSB) at specific target loci. A re-engineered meganuclease was designed for specific cleavage of an endogenous target sequence adjacent to a transgenic insect control locus in cotton. The combination of targeted DNA cleavage and homologous recombination–mediated repair made precise targeted insertion of additional trait genes (hppd, epsps) feasible in cotton. Targeted insertion events were recovered at a frequency of about 2% of the independently transformed embryogenic callus lines. We further demonstrated that all trait genes were inherited as a single genetic unit, which will simplify future multiple-trait introgression.
Plant Journal | 2013
Vesna Djukanovic; Jeff Smith; Keith S. Lowe; Meizhu Yang; Huirong Gao; Spencer Jones; Michael Nicholson; Ande West; Janel Lape; Dennis L. Bidney; Saverio Carl Falco; Derek Jantz; Leszek Alexander Lyznik
The I-CreI homing endonuclease from Chlamydomonas reinhardti has been used as a molecular tool for creating DNA double-strand breaks and enhancing DNA recombination reactions in maize cells. The DNA-binding properties of this protein were re-designed to recognize a 22 bp target sequence in the 5th exon of MS26, a maize fertility gene. Three versions of a single-chain endonuclease, called Ems26, Ems26+ and Ems26++, cleaved their intended DNA site within the context of a reporter assay in a mammalian cell line. When the Ems26++ version was delivered to maize Black Mexican Sweet cells by Agrobacterium-mediated transformation, the cleavage resulted in mutations at a co-delivered extra-chromosomal ms26-site in up to 8.9% of the recovered clones. Delivery of the same version of Ems26 to immature embryos resulted in mutations at the predicted genomic ms26-site in 5.8% of transgenic T(0) plants. This targeted mutagenesis procedure yielded small deletions and insertions at the Ems26 target site consistent with products of double-strand break repair generated by non-homologous end joining. One of 21 mutagenized T(0) plants carried two mutated alleles of the MS26 gene. As expected, the bi-allelic mutant T(0) plant and the T(1) progeny homozygous for the ms26 mutant alleles were male-sterile. This paper described the second maize chromosomal locus (liguless-1 being the first one) mutagenized by a re-designed I-CreI-based endonuclease, demonstrating the general utility of these molecules for targeted mutagenesis in plants.
The FASEB Journal | 2013
Séverine Ménoret; Sandra Fontanière; Derek Jantz; Laurent Tesson; Reynald Thinard; Séverine Rémy; Claire Usal; Laure-Hélène Ouisse; Alexandre Fraichard; Ignacio Anegon
Despite the recent availability of gene‐specific nucleases, such as zinc‐finger nucleases (ZFNs) and transcription activator‐like nucleases (TALENs), there is still a need for new tools to modify the genome of different species in an efficient, rapid, and less costly manner. One aim of this study was to apply, for the first time, engineered meganucleases to mutate an endogenous gene in animal zygotes. The second aim was to target the mouse and rat recombination activating gene 1 (Rag1) to describe, for the first time, Rag1 knockout immunodeficient rats. We microinjected a plasmid encoding a meganuclease for Rag1 into the pronucleus of mouse and rat zygotes. Mutant animals were detected by PCR sequencing of the targeted sequence. A homozygous RAG1‐deficient rat line was generated and immunophenotyped. Meganucleases were efficient, because 3.4 and 0.6% of mouse and rat microinjected zygotes, respectively, generated mutated animals. RAG1‐deficient rats showed significantly decreased proportions and numbers of immature and mature T and B lymphocytes and normal NK cells vs. littermate wild‐type controls. In summary, we describe the use of engineered meganucleases to inactivate an endogenous gene with efficiencies comparable to those of ZFNs and TALENs. Moreover, we generated an immunodeficient rat line useful for studies in which there is a need for biological parameters to be analyzed in the absence of immune responses.—Ménoret, S., Fontanière, S., Jantz, D., Tesson, L., Thinard, R., Rémy, S., Usal, C., Ouisse, L.‐H., Fraichard, A., Anegon, A. Generation of Rag1‐knockout immunodeficient rats and mice using engineered meganucleases. FASEB J. 27, 703–711 (2013). www.fasebj.org
BMC Biotechnology | 2012
Mauricio S. Antunes; Jeff Smith; Derek Jantz; June I. Medford
BackgroundA systematic method for plant genome manipulation is a major aim of plant biotechnology. One approach to achieving this involves producing a double-strand DNA break at a genomic target site followed by the introduction or removal of DNA sequences by cellular DNA repair. Hence, a site-specific endonuclease capable of targeting double-strand breaks to unique locations in the plant genome is needed.ResultsWe engineered and tested a synthetic homing endonuclease, PB1, derived from the I-CreI endonuclease of Chlamydomonas reinhardtii, which was re-designed to recognize and cleave a newly specified DNA sequence. We demonstrate that an activity-optimized version of the PB1 endonuclease, under the control of a heat-inducible promoter, is capable of targeting DNA breaks to an introduced PB1 recognition site in the genome of Arabidopsis thaliana. We further demonstrate that this engineered endonuclease can very efficiently excise unwanted transgenic DNA, such as an herbicide resistance marker, from the genome when the marker gene is flanked by PB1 recognition sites. Interestingly, under certain conditions the repair of the DNA junctions resulted in a conservative pairing of recognition half sites to remove the intervening DNA and reconstitute a single functional recognition site.ConclusionThese results establish parameters needed to use engineered homing endonucleases for the modification of endogenous loci in plant genomes.
Molecular Therapy | 2017
Daniel T. MacLeod; Jeyaraj Antony; Aaron J. Martin; Rachel J. Moser; Armin Hekele; Keith J. Wetzel; Audrey E. Brown; Melissa A. Triggiano; Jo Ann Hux; Christina Pham; Victor V. Bartsevich; Caitlin Turner; Janel Lape; Samantha Kirkland; Clayton W. Beard; Jeff Smith; Matthew L. Hirsch; Michael Nicholson; Derek Jantz; Bruce McCreedy
Adoptive cellular therapy using chimeric antigen receptor (CAR) T cell therapies have produced significant objective responses in patients with CD19+ hematological malignancies, including durable complete responses. Although the majority of clinical trials to date have used autologous patient cells as the starting material to generate CAR T cells, this strategy poses significant manufacturing challenges and, for some patients, may not be feasible because of their advanced disease state or difficulty with manufacturing suitable numbers of CAR T cells. Alternatively, T cells from a healthy donor can be used to produce an allogeneic CAR T therapy, provided the cells are rendered incapable of eliciting graft versus host disease (GvHD). One approach to the production of these cells is gene editing to eliminate expression of the endogenous T cell receptor (TCR). Here we report a streamlined strategy for generating allogeneic CAR T cells by targeting the insertion of a CAR transgene directly into the native TCR locus using an engineered homing endonuclease and an AAV donor template. We demonstrate that anti-CD19 CAR T cells produced in this manner do not express the endogenous TCR, exhibit potent effector functions in vitro, and mediate clearance of CD19+ tumors in an in vivo mouse model.
Molecular Plant | 2015
Arik Honig; Ira Marton; Michal Rosenthal; Jeff Smith; Michael Nicholson; Derek Jantz; Amir Zuker; Alexander Vainstein
The use of sequence-specific nucleases for plant genomic DNA mutagenesis is an exciting and rapidly developing technology (Voytas and Merchant, 2013; Baltes and Voytas, 2014). To date, most mutated plants have been recovered from transgenic plants stably expressing nucleases. However, transient nuclease delivery by plant DNA- and RNA-based viral vectors followed by regeneration of plantlets from modified tissues has emerged as an alternative, efficient strategy in some plant species (Marton et al., 2010; Baltes et al., 2014).
Nature Biotechnology | 2018
Lili Wang; Jeffrey Smith; Camilo Breton; Peter Clark; Jia Zhang; Lei Ying; Yan Che; Janel Lape; Peter Bell; Roberto Calcedo; Elizabeth L. Buza; A. Saveliev; Victor Bartsevich; Zhenning He; John H. White; Mingyao Li; Derek Jantz; James M. Wilson
Clinical translation of in vivo genome editing to treat human genetic diseases requires thorough preclinical studies in relevant animal models to assess safety and efficacy. A promising approach to treat hypercholesterolemia is inactivating the secreted protein PCSK9, an antagonist of the LDL receptor. Here we show that single infusions in six non-human primates of adeno-associated virus vector expressing an engineered meganuclease targeting PCSK9 results in dose-dependent disruption of PCSK9 in liver, as well as a stable reduction in circulating PCSK9 and serum cholesterol. Animals experienced transient, asymptomatic elevations of serum transaminases owing to the formation of T cells against the transgene product. Vector DNA and meganuclease expression declined rapidly, leaving stable populations of genome-edited hepatocytes. A second-generation PCSK9-specific meganuclease showed reduced off-target cleavage. These studies demonstrate efficient, physiologically relevant in vivo editing in non-human primates, and highlight safety considerations for clinical translation.
Molecular Therapy | 2016
Christina Pham; Aaron Martin; Jeyaraj Antony; Daniel T. MacLeod; Audrey E. Brown; Michael Nicholson; Jo Ann Hux; Caitlin Turner; Wendy Sharer; Bruce McCreedy; Victor Bartsevich; Ginger Tomberlin; Janel Lape; Jeffrey S. Smith; Derek Jantz
The manufacture of CAR-T cells depends on peripheral blood donations that contain T cells of sufficient quality and quantity. Currently, many CAR-T programs rely on autologous T cells, but several technical and commercial challenges hinder development. The majority of CAR-T trials have enrolled leukemia or lymphoma patients, many of which are unsuitable donors for CAR-T production due to their disease state or to previous treatments with lymphodepleting agents. In addition, a custom CAR-T production run for each patient is time consuming, lacks standardization and may present regulatory challenges. An alternative strategy is to source T cells from healthy donors and produce large batches of allogeneic CAR-T cells. Allogeneic T cells, however, will display mismatched human leukocyte antigens (HLA) that will be recognized by the recipients’ immune systems, contributing to immune rejection of engrafted CAR-T cells. Additionally, donor T cells will recognize the mismatched HLAs present in the recipient, contributing to graft-versus-host immune pathology. Both undesired immune responses are predicated on interactions between HLA and T cell receptors (TCR), and while the therapeutic effectiveness of CAR-T cells with targeted deletions in TCR genes has been reported by several groups, studies featuring both TCR and HLA deletion are limited. Here, we describe the use of meganucleases engineered to target regions of the TCR α chain constant region and β-2 microglobulin genes to generate TCR and HLA class I knockout primary human T cells. Both nucleases generate knockouts with approximately 75% efficiency and are well-tolerated by primary T cells from at least four separate donors. Purified double knockout cells do not demonstrate functional disadvantages in terms of proliferation or cytokine production, but do exhibit reduced allostimulatory potential toward HLA-mismatched T cells. Together, these findings demonstrate the feasibility of generating therapeutic quantities of CAR-T cells with reduced allo-reactive potential and collateral toxicity to normal tissues in recipients.
Molecular Therapy | 2016
Victor V. Bartsevich; John Morris; Ginger Tomberlin; Caitlin Turner; Wendy Sharer; Michael Nicholson; Jeff Smith; Nag Kollu; Rachel James; Robin L. Armstrong; Matthew L. Hirsch; Derek Jantz
The field of genome editing has exploded in recent years. However, despite being the only nuclease naturally evolved for genome editing, meganucleases have largely remained behind the scenes compared to ZFNs, TALENs, and CRISPRs due to difficulties in modifying their DNA-recognition specificity. We have developed a next-generation meganuclease platform called “ARCUS” that overcomes these production difficulties and can produce nucleases with customized activity and specificity. Unlike some other genome editing technologies, ARCUS nucleases are capable of distinguishing target sites that only differ by 1 base pair. We will present the ARCUS platform and one such example of a meganuclease engineered to distinguish the dominant P23H point mutation in the rhodopsin gene from its wild type allele for a possible gene therapy of retinitis pigmentosa