Zusammenfassung der Ressource
Advanced Concepts
in Stem Cell Biology
- Reprogramming
Cell Fate
- Nuclear Transfer
- Somatic cell nucleus is
injected into an
enucleated oocyte, which
are then fused together
- Reprograms
the nucleus
- Resulting embryo
generates an
identical clone of the
donor organism
- e.g. tadpoles,
Dolly the sheep
- Cell Fusion
- Two cell types
are combined
together
- Just the
cytoplasm
fused
- If DNA replication and
cell division does not
occur, a binucleated
heterokaryon is
produced
- If it does, a
synkaryon is
produced
instead
- Can be euploid (equal
number of chromosomes
- fuse cells from the
same species)
- Or aneuploid
(abnormal number
of chromosomes -
fuse cells from
different species)
- Transcription-Factor
Transduction
- TFs such as c-Myc,
Oct4, Sox2 and Klf4
activate pluripotency in
a somatic cell
- Causes it to divide
into induced
pluripotent stem
cells (iPS cells)
- Uses
- Patient-specific
cell therapy
- Drug
screening
- Human disease
modelling
- Lineage Specifiers
- Suggested that
pluripotency factors such as
Oct4 and Sox2 also
function to specify a lineage
during ESC differentiation
- Overexpression of
certain factors leads
to differentiation of a
specific lineage
- Oct4 specifies
the mesoderm
- Sox2 specifies the
neuroectoderm
- Extrinsic
cytokine
signalling
- Mechanism which
allows control of the
expression of the various
pluripotency factors
which determine cell fate
- ESCs remain
undifferentiated due to all
of the key pluripotency
factors being expressed
at similar levels
- No factor becomes
dominant, and so
differentiation does
not occur
- Key to stem cells
self-renewing and
maintaining of their
undifferentiated state