lecture 17 - recombinant dna tech 4 Flashcards
what are the two key properties of stem cells
- ability to self-renew (can go through numerous cycles of cell division while maintaining undifferentiated state)
- differential potential to differentiate into specialized cell types
what are totipotent stem cells? give example
cells can differentiate into embryonic and extra-embryonic cell types
ex. zygote
what are pluripotent stem cells? give example
descendants of totipotent cells and can differentiate into cells derived from any of the three germ layers
ex: embyonic stem cell
what are multipotent stem cells? give example
can produce only cells of a closely related family of cells
ex. hematopoietic stem cells differentiate into RBC, WBC, platelets, etc
what are unipotent stem cells? give example
can produce only one cell type, but have the property of self-renewal which distinguishes them from non-stem cells
e.g. muscle stem cells.
what is somatic cell nuclear transplataion SCNT
when you remove the nulceus of an egg and replace it with nucleus of parent cell
what process is used for animal cloning
SCNT
what are issues associated with animal cloning
- only small percentage of cloned embyos have developed normally to birth and many cloned animals echibit defects
- many epigentic changes must be reversed in donor animal nucleus in order for genes to be expressed/repressed appropriately for early stages of dev
what are stem cells isolated from early embroys at blastocyst stage called and what can they do
embryonic stem (ES) cells; these are able to differentiate into all cell types of the three germ layers
how are transgenic animals made
introducing genes from one species into genome of another
what are the methods for introducing a transgene
- retrovirus
- miroinjection into eggs/fertizilied eggs
- embryonic stem cells
how do you design a transgene
- select for integration
- choosing promoter for expression
what is selection for integration for transgenes based on
antibiotic resistance genes but these can be later excised to prevent antibiotic resistance in animals
what is the cre-lox system
site-specific recombination system which can modify struct, control gene expression and delete genes
what are cre and loxP roles in cre-lox system
cre: recombinase
loxP: recognition site for recombinase
what was the first transgenic animal? when was it? what were the changes? who did it
expressed rat growth hormone gene in mice liver in 1982 by richard palmer and ralph brinster
what was the first transgenic sheep? when was it? what were the changes? how was it done?
tracy was injected with human alpha-1-antitrypsin to treat emphysema/cystic fibrosis. done by microinjecting a zygote in 1990
who was the first closed transgenic animals
molly and dolly (1997)
what are CAR-T cells and what are they used for
inject CAR (chimeric antigen receptor) into T cells using retroviral vector. used to treat blood cancers for now
what are Induced Pluripotent Stem Cells and what do they do
transform skin cells into ES cells using viruses to introduce stem cell master regulatory genes. can be used to treat some diseases and replace nonfunctional tissues
what are the master regulatory genes necessary for iPSCs
OCT4, SOX2, KLF4, c-Myc
