All cells in a person have the same DNA Yet eye cells differ from nose cells Central dogma of biology Genetic engineeri ng Tissue therapy

Other Cells Matrix Molecules Self-Renewal Soluble Factors Differentiation Little, et al. Chemical Reviews (2008).

 Low stress levels  Regular exercise  Enriching experiences  Learning new information  Healthy diets: rich in antioxidants  Avoid excessive drinking

Skin cells iPS cells

 Are fully differentiated cells  Can not become any other cell type  Can only divide to make more fibroblasts  Contact inhibition

 Randomly inserts DNA into genome of cells  Can make special retroviruses with whatever gene you want  Can’t really control how many copies of genes

 Only turn on a drug resistance gene when stem cell state  Do this by using a gene that is only expressed in stem cells  Add drug resistance to promoter region of that gene  Takes around 16 days for resistance gene to be expressed- some secondary change

 Sox2- Self Renewal  Oct4- Differentiation switch  Klf4- p53 pathway, Oncogene  c-Myc- Global Histone Acetylation, Oncogene

 Without Oct 3/4 or Klf: no colonies  Without Sox2: rough morphology  Without c-Myc: flatter cells, now know actually can do without c-myc-just very low efficiency

 Tried to inject into blastocyst to make baby mice but failed  Final and best test of pluripotency

 Still working with mouse model  Used different drug selection marker  Same 4 genes  Much more closely resemble ES cells

Treatment of DNA with bisulfite converts cytosine residues to uracil, but leaves 5-methylcytosine residues unaffected Introduces specific changes in the DNA sequence that depend on the methylation status of individual cytosine residues

Used Oct3/4, Sox2, Nanog and Lin28

 Used the animal’s own cells- no immune rejection!  Transfected with all four genes, but c- myc taken out after time- prevent tumors!  Sickle Cell Anemia has known genetic basis-so target that gene and change it back to normal!  Inject it back into the animal after radiation to reconstitute the whole blood system!

 Any disease with a single genetic mutation could be easily cured!  Tissue regeneration after accidents or diseases  “Nanobots”  Companies have already started testing iPS for therapy

 No way FDA will approve a therapy with an oncogene  Use of retroviruses can lead to mutations and cancers  So many changes in the DNA can be harmful  Probably hard to target to some areas