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Published byChristian Simmons Modified over 9 years ago
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I-SceI-mediated Genome Editing in the Canine Model Kiem lab Applications Meeting Feb 23, 2009
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GFP Targeting Strategy. Gene Correction With A Dual IDLV System Vector Provirus Target GGGATCCAC TAGGGATAACAGGGTAAT CGGTC GCCACC ATG GTG TGA TAG GGC GAG GAG I-SceI 5’ LTRRREcPPThPGKGFP’WPRE3’ LTRSFFVMGMT P140K Repair Template GTC CTG CTG GAG TTC GTG TAA TGT ACA AGT AA 5’ LTRRREcPPTSFFVI-SceIWPRE3’ LTR I-SceI IDLV HA tag 5’ LTRRREcPPThPGKWPRE3’ LTR Stop codon ( 14 a.a.) GGGATCCAC CGGTC GCCACC ATG GTG AGC AAG GGC GAG GAG 14-GFP
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The donor template IDLV and I-SceI IDLVs were delivered into Target D17 cells The volume for both IDLVs used is indicated above each graph. Gene Correction Efficiency in Canine D17 Cells: Dual IDLV System 02004006008001000 10 0 1 2 3 4 SSC-H GFP 8.3e-3 02004006008001000 10 0 1 2 3 4 SSC-H GFP 1.44 02004006008001000 10 0 1 2 3 4 SSC-H GFP 2.44 02004006008001000 10 0 1 2 3 4 SSC-H GFP 3.75 0l0l25 l50 l100 l
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GFP and I-SceI Expression in D17 Cells treated with the Dual IDLV System I-SceI GFP D17 cells targets were transduced with the two IDLVs at different relative ratios as indicated (I-SceI:repair template). I-SceI:template
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Targeting with An All-In-One IDLV System Gene Target 5’ LTRRREcPPThPGKGFP’WPRE3’ LTRSFFVMGMT P140K I-SceI + Repair Template 5’ LTRRREcPPThPGK 14-GFP WPRE3’ LTRSFFVI-SceI HA tag I-SceI
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Analysis of Gene Correction in D17-GFP’ Cells. All-in-one IDLV System 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.061 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.33 02004006008001000 10 0 1 2 3 4 SSC-H GFP 1.72 02004006008001000 10 0 1 2 3 4 SSC-H GFP 2.44 0 l 1l1l10 l50 l The donor template and I-SceI were delivered into D17 targets using the all-in-one IDLV. The volume of IDLV used is indicated above each graph.
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Analysis of Targeted D17 cells 0200400600 800 1000 10 0 1 2 3 4 SSC-H GFP 1.45 02004006008001000 10 0 1 2 3 4 SSC-H GFP 91.8 FACS sort PCR amplification of the gene target Reverse primer Target-specific! hPGKGFP’ Forward primer Gene target hPGK 14-GFP Repair template Sequence analysis 73 clones sequenced 41% corrected target 59% original target Original target Clone 1 (+1bp) Clone 2 (corrected) Clone 3 (original) Clone 4 (original) Clone 5 (corrected) Clone 6 (original) I-SceI site Stop codons
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Transduction of Canine CD34 + Cells with Target Vector (O/N tdn) CFU countsCFU PCR analysis 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 0.49 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 2.8 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 3.4 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 7.1 MockMOI=0.5MOI=1MOI=10 MGMT intracellular staining on liquid cultures 14d after transduction
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Transduction of Canine CD34 + Cells with The Target Vector (O/N v. O/N+4h tdn) 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 0.14 0200400 600 800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 1.8 0 200 400600800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 2.24 0200400600800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 2.5 0200400600800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 0.085 0200400600800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 1.88 0200400600800 1000 10 0 1 2 3 4 SSC-H MGMT-PE 5.45 02004006008001000 10 0 1 2 3 4 SSC-H MGMT-PE 8.46 Mock MOI=1 MOI=10MOI=20 O/N O/N+4h MGMT intracellular staining on liquid cultures 10d after transduction
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02004006008001000 0 1 2 3 4 SSC-H Isotype-PE 0200400600 800 1000 0 1 2 3 4 SSC-H CD34-PE 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.22 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.44 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.61 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.84 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.34 02004006008001000 10 0 1 2 3 4 SSC-H GFP 0.78 02004006008001000 10 0 1 2 3 4 SSC-H GFP 1.05 02004006008001000 10 0 1 2 3 4 SSC-H GFP 1.21 0 l2l2l10 l50 l ML3-GFP’ MOI=1 ML3-GFP’ MOI=10 IDLV Gene Conversion in The Canine CD34 + Cell Line ML3
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Efficient Lentiviral Transduction of ML3 Cells MockMOI=0.5 MOI=1MOI=10 RSCSPGW2 ML3 cells can be efficiently transduced with an integrating lentivirus ML3 and D17 target cells have comparable amounts of the target vector provirus Relative Vector Provirus Copy Number
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Dog DLA-identical transplantation setting Donor DLA identical recipient I. Collection and transduction of CD34 + cells with LHE site- containing integrating lentiviral vector II. Infusion of cells after conditioning by irradiation III. Iterative treatments with O 6 BG and BCNU or temozolomide followed by collection of CD34 + cells with stably integrated LHE site-containing target. VI. Infusion of cells after myeloablative conditioning V. Transduction with IDLV encoding repair template and I-SceI IV. Investigate repair efficiency in canine progenitors
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In Vivo Selection to Increase the Percentage of Canine CD34 Cells with I-SceI Targets Days after Transplantation
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Summary Efficient IDLV targeting using an EGFP reporter system A ratio of I-SceI IDLV: Donor IDLV 4.4:1 gave efficient targeting (lowest ratio tried to date) Similar efficiency with all-in one IDLV vector in D17 cells Demonstrated Gene Correction at the Molecular level Established conditions for efficient introduction of target vector in canine CD34+ cells
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Future Experiments Investigate the effect of the repair template : I-SceI ratio on gene repair efficiency and toxicity Test a negative selection marker (e.g. Cytosine Deaminase) to eliminate background random integrants from the IDLV. Evaluate LHE-mediated genome editing of canine hematopoietic progenitors and repopulating cells. Generate an I-AniI-mediated reporter system
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