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Cloning in Nature Parthenogenesis Monozygotic twins (embryo splitting) (incomplete embryo splitting) Egg Cell and Sperm Cells Pg. 661 Ca 2+ Wave Metaphase arrest Ca2+ and Egg Activation SEP “Calcium wave” Cleavage Stage Embryos Pre-compaction Compaction Cadherin (Homophilic Cell Adhesion Molecule) Blastocycst Uterus Inner Cell Mass (ICM) Blastocyst Blastocoel Trophoblast 50 µm Pre-implantation Development (~ 7 days in humans) Mammals Cloned by Embryo Splitting Sheep Cattle Mouse Pig Horse Rhesus monkey Blastomere Isolation “Tetra” Mammals Cloned by SCNT Sheep Mouse Cattle Pig Mule “Dolly” “Copy Cat” Horse Goat Rabbit Cat Dog Gaur Removal of genetic material from oocyte Transfer of diploid nucleus from adult somatic cell or Embryonic cell into “enucleated” oocyte Oocyte Activation Cleavage divisions of “reconstructed” embryo SCNT in Mice Injected somatic nucleus Condensed Chromosomes Pseudo-pronuclei Ca 2+ injection cytochalasin Removal of genetic material from oocyte Transfer of diploid nucleus from adult somatic cell or Embryonic cell into “enucleated” oocyte Oocyte Activation Cleavage divisions of “reconstructed” embryo Copy Cat Somatic cell donor “mom” Copy Cat Somatic cell donor “mom” Inactive X Chromosome (“Barr Body”) X Chromosome Inactivation ICM cells of Blastocyst Copy Cat Somatic cell donor “mom” Neural Plasticity Environment has a significant role in establishing and maintaining neural connections in the brain Stem Cell Concept Pluripotent Multipotent Unipotent Regenerative Medicine Stem Cells Transplant into patients Pluripotent Stem Cells Mouse Chimeras with Embryonic Stem Cells Science 282: 1145-1147 November 6, 1998 Human Embryonic Stem Cell Colony Stem Cells Mouse “feeder” cells Normal Karyotype in Cultured Human Embryonic Stem Cells Cultured Cells Remain Undifferentiated Telomerase Activity Undifferentiation “Markers” Oct4 SSAE4 Teratoma Ectoderm (squamous epithelium) Mesoderm (bone and cartilage) Endoderm (gut epithelium) Embryonic Stem Cell Signaling Pathways OCT4 These Pathways are necessary for maintaining the undifferentiated State Nature 456: 344-349 November 20, 2008 Science 318: 1917-1920 December 21, 2007 Science 321: 1218-1221 August 29, 2008 iPS Cell Colony from Patient with ALS QuickTime™ and a TIFF (L ZW) d eco mpres sor are nee ded to s ee this picture. Reprogramming Genes: OCT4, SOX2, KLF4, c-MYC Neurons from iPS Cells Derived from ALS patient QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. Tissues with Adult Stem Cells Bone marrow/peripheral blood/umbilical cord Blood vessels Brain/spinal cord Skeletal muscle Colon Liver Pancreas Retina/cornea Skin Dental pulp Adult Stem Cell Life-long Multipotent Plasticity? Adult Stem Cells Multipotent Progenitor Cells Stem Cell Niche Stem Cell (Common Myeloid progenitor) (Common Lymphoid progenitor) Signaling Pathways for Self Renewal in Adult Stem Cells Signals produced with the HSC niche Cytkine Signaling via Jak/STAT Pathway Cytokines in Hematopoiesis Bone Marrow (Common Myeloid progenitor) (Common Lymphoid progenitor) Myeloid Leukemia Tumor Growth (~ 10 yrs) (~ 8 yrs) (~ 7.5 yrs) (~ 100 days/pop doubling) Myeloid Leukemia CD34+ Myeloid Leukemia CD34+ CD34+ No Wnt Molecules Pathway OFF INACTIVE (No cell division) Self-renewal Proliferation Pathway ON (family of ~ 20 proteins) ACTIVE Wnt Target Genes Self-renewing Proliferation Cyclin D Nanog SOX2 c-myc LIN28 BMP4 FGF MMP Pathway Always ON in Cancer (family of ~ 20 proteins) Activating Mutations Wnt FRAT catenin Wnt Target Genes Inactivating Mutations Axin APC CONSTANT Proliferation Cyclin D Nanog SOX2 c-myc LIN28 BMP4 FGF MMP Tumor Formation Phenotypically Different Cells Varying Degrees of Differentiation Different Proliferative Potential Different Lifespans All Cell Types in the Tumor Implications for Cancer Chemotherapy December 4, 2008 Tumorigenic Potential Assay Inject tumor cells into SCID mice Examine mice after 8 weeks ~ 0.0001 - 0.1% of Cancer cells are Tumorigenic/Leukemogenic Factors Affecting Outcome of Experiment Prolonged Observation period Severely immunocompromised mice Preincubation of injected tumor cells in ECM proteins