How to construct transgenic mice

Transcription

1 How to construct transgenic mice Sandra Beer-Hammer Autumn School 2011 Bad Schandau Pharmakologie und Experimentelle Therapie (APET)

2 Overview History Generation of embryonic stem (ES) cell lines Generation of knock-out mice Generation of transgenic mice ENU-mutagenesis Seite 2

3 Time line: from pluripotent cells Seite 3

4 Time line: from pluripotent cells to transgenic mice Seite 4

5 to the Nobel Prize for Medicine 2007 Seite 5

6 to the Nobel Prize for Medicine 2007 Seite 6

7 to the Nobel Prize for Medicine 2007 Seite 7

8 Where do ES cells come from? Seite 8

9 Cells from ICM differentiate to the embryo Trophoectoderm Inner Cell Mass Blastocoel Seite 9

10 How to generate ES cell lines? Culture of blastocysts Day 5-6 Outgrowth of ICM and trophoblasts Isolation of ICM Day 9 Morphological screening of single colonies and isolation Day 14 ES cell line discard Seite 10

11 Morphology of blastocysts and trophoblasts Blastocysts Trophoblasts Seite 11

12 Cell culture of ES cell lines - Cultivation on feeder cells (embryonic fibroblasts) - Cultivation in LIF (Leukemia inhibitory factor) containing medium ES cell culture on fibroblasts Seite 12

13 Origin of ES cells most ES cell lines from 129 strain (E14, R1 etc) high frequency of teratocarcinomas selection of chimera via skin colour (recipient blastocyst from C57BL/6) strain 129 is agouti (A/A) and light brown (b/b) C57BL/6 is non-agouti (a/a) and black (B/B) chimera are agouti/black germ line transmission: F1 mice (chimxc57bl/6) are agouti (A/a) also ES cell lines from C57BL/6 and BALB/c Seite 13

14 Methods gene inactivation gene-deficient or knock-out mice additional genetic information transgenic mice knock-in mice Seite 14

15 Generation of gene deficient mice knock-out Seite 15

16 Targeting vector 1. Seite 16

17 Targeting vector Careful planning of all steps, including PCR and Southern Blot strategies Functional inactivation of gene of interest Insertion of a selection marker (neo) into the 1. exon (insertion mutagenesis) Replace 1. exon with selection marker (replacement mutagenesis) Insertion / replacement of essential protein domain (other exon than 1. exon) Seite 17

18 Planning a targeting vector 5. December 2002 The mouse genome is mapped Seite 18

19 Planning a targeting vector Known: cdna sequence (full-length) B cell receptor Gene Blast: Search for homologous genomic sequence around 10 min later.. Seite 19

20 Classical gene inactivation HSV-TK Bacterial aminoglykosid-phosphotransferase : resistance for G418 (positive selection) HSV-TK Viral thymidine kinase: sensitive to Ganciclovir (negative selection) Seite 20

21 Positive and negative selection Seite 21

22 Generation of gene deficient mice knock-out 2. PCR screening Typical gene targeting experiment: Seite 22

23 Strategies for screeening: PCR Seite 23

24 Strategies for screeening: Southern Blot Seite 24

25 Generation of gene deficient mice knock-out 3. Seite 25

26 Isolation of Blastocysts day 3.5 after mating Seite 26

27 Injection of ES Cells Holding pipette Blastocyst (2.5 days) Injection pipette with ES cells Seite 27

28 Uterus transfer Seite 28

29 Generation of gene deficient mice knock-out 4. Seite 29

30 Testing of Germline Transmission E14 mice w t w t + / - + / - Agouti mice carry one allele of the mutated gene kb Chimeric mice are mated with C57BL/6 mice Southern Blot Seite 30

31 + / + + / - - / - Verification of KO kb 2.0 LTbR 1.2 GAPDH Northern Blot Western Blot Seite 31

32 Future of knock-out mice?? Seite 32

33 Conditional Gene-Targeting Introduction of point mutations Delete regulatory sequences neo genetically modified ES cell te Cre - expression Gene replacement Tissue-specific knock-outs Inducible knock-outs transient Cre (Frt, Flrt) Expression Seite 33

34 Conditional Gene-Targeting neo genetically modified ES cell te Cre - expression transient Cre (Frt, Flrt) Expression Seite 34

35 Conditional Gene-Targeting: 1. Introduction of point mutations Seite 35

36 Conditional Gene-Targeting: 2. Delete regulatory sequences Which role has the Eµ Enhancer for V(D)J recombination? Seite 36

37 Conditional Gene-Targeting: 3. Gene replacement Seite 37

38 Conditional Gene-Targeting: 4. Tissue-specific knock-out Seite 38

39 Conditional Gene-Targeting: 4. Tissue-specific knock-out Seite 39

40 Conditional Gene-Targeting: Combination Cre/Flp Seite 40

41 Conditional Gene-Targeting: 5. Inducible knock-out Seite 41

42 Conditional Gene-Targeting: 5. Inducible knock-out Seite 42

43 Conditional Gene-Targeting: 5. Inducible knock-out Seite 43

44 Conditional Gene-Targeting: 5. Inducible knock-out Seite 44

45 Condtional Gene-Targeting: Gene ablation Seite 45

46 Conditional Gene-Targeting: Gene ablation CD19-Cre CD4-Cre Seite 46

47 The Cre-Zoo (constitutive or inducible) Fluorescent proteins Light-inducible cation channel Cre expression Cre inducible DTR Inducible Cre Inducible gene expression LacZ expression Light-inducible anion channel From Johansson, Genesis 2010 Seite 47

48 Knock-out versus Transgenic Mice Knock-out/knock-in mice Transgenic mice -Targeted inactivation/mutation - Random integration into the genome of gene in the endogenous locus - Microinjection into pronuclei of oocytes - Introduction of mutation in ES cells via homologous recombination - Expression is dependent on integration locus - Tissue-specific switching on and off - Tissue-specific expression not always assessable Seite 48

49 Generation of Transgenic Mice Seite 49

50 Practical procedure: isolation of oocytes Cycle of mice: 4 days day/night cycle ovulation: every 4 days, around 5hrs after darkening mating: 1-2 female / male (afternoon) plug check next morning around 50% of mice in cycle: 5-10 oocytes superovulation with gonadotropines: oocytes isolation out of the oviduct next day (d2.5) Seite 50

51 Microinjection of DNA Zona pellucida Injection pipette Holding pipette male pronucleus Embryo (1-cell stadium) female pronucleus nucleolus Seite 51

52 Practical procedure: transfer of the oocytes vasectomized male were mated with female (plug check) pseudopregnant female oocytes are injected into the oviducts Seite 52

53 The construct: cdna or genomic? cdna often easier to isolate and smaller often less expression with cdna constructs (enhancer/silencer) prokaryotic vector-sequences can inhibit the gene expression no limitations on the length for the microinjection (BACs or even YACs) mostly integration of two transgenes transgene should be differentiated from the endogenous DNA/RNA/protein: - reduction of the 3 not-translated region - insertion of silent point mutations (generation of restriction sites) - insertion of tags (HA, his, myc, strep, etc.) Seite 53

54 Construction of DNA and RNA Expression Control T- and B-cell specific promotor (B. Iritani, 1997) Seite 54

55 Protein Expression in T and B Cells Seite 55

56 Classical transgenic mice frequently used in immunology Examples for antigen-receptor transgenic mice B cells: MD4-anti HEL IgM/IgD transgenic mice T cells: - OT-1: TCR specific for the SIINFEKL peptide of ovalbumine presented on k b - OT-2: TCR specific for chicken ovalbumin in the context of I-A b - DO11.10: TCR specific for chicken ovalbumin in the context of I-A d not all B-/ T-cells express the transgenic receptor (editing), monoclonal antibodies as anti-idiotypes /anti-clonotypes are available to detect the transgenic B- / and T-cells Seite 56

57 Rosa 26-Locus - Ubiquitary expressed gene - Gene product with unknown function - high gene targeting frequence Seite 57

58 Transgenic mice: Various possibilities Seite 58

59 BAC Transgenic (or knock-out) Mice Seite 59

60 Find the Right BAC (bacterial artificial chromosome) From Johansson, Genesis 2010 Seite 60

61 BAC Transgenic Mice Purify DNA and inject into pronucleus From Johansson, Genesis 2010 Seite 61

62 ET cloning versus Recombineering From Johansson, Genesis 2010 Seite 62

63 ET cloning versus Recombineering From Johansson, Genesis 2010 Seite 63

64 BAC knock-out Seite 64

65 BAC knock-out Method Overview I 1.) Creating the targeting vector with homologues recombination in E. coli pbad electroporate WI1 2.) 28 C NEO r electroporate pbad WI1 3.) Picking Kana/Chloramph resistant clones / check by PCR + DNA restriction Seite 65

66 BAC Knock-out Method Overview II 4.) pbad electroporate WI1 +NEO 28 C 5.) Thymidine kinase electroporate pbad WI1 +NEO 6.) Picking Amp/Kana/Chloramph resistant clones / check by PCR + DNA restriction Seite 66 Pharmakologie und Experimentelle Therapie (APET)

67 Verification of Modified BAC Purify DNA and electroporate into ES cells Seite 67

68 Two possibilities in genetics Seite 68

69 Strategies for mutagenesis in mice g-irradiation (frequency: x 10-5 / Locus) spontaneous mutations (frequency: 5 x 10-6 / Locus) Ethylnitroso-urea (frequency: 150 x 10-5 / Locus) Advantage: single point mutations, high troughput Disadvantage: no molecular marker for cloning Seite 69

70 ENU-mutagenesis: GSF Seite 70

71 ENU-mutagenesis: from the hypothesis. ENU mutagenesis of C57BL/6 mice: 2649 F1, 4584 F3 mice specific phenotype: TNF-production upon stimulation with different TLR-stimuli isolation of peritoneal macrophages under anesthesia (mutants can be breed) Seite 71

72 .to the identification of a locus (2003). Identification of the LPS2 - mutation Seite 72

73 to the Nobel prize for medicine 2011 Identification of the LPS2 - gene Seite 73

74 Thank you! Seite 74