Totipotent Stem cells
Using stem cells for replacing damaged tissues and organs
Cells in our bodies have the same amount of DNA, and that DNA is completely identical! So how come a muscle cell and a brain cell both have very different structure and function despite that? How can cells be different to one another yet carry the same genetic information which codes for the same proteins? Indeed, how come most of a cell’s DNA is not translated?
The answer is that only the relevant genes are active in a given cell at a given time. The rest are inhibited because their transcription and/or translation is switched off. So how do cells become specialised?
Totipotent Stem Cells
Stem cells, just like tree stems are to branches, are the common source of all different kinds of cells. Cells start out as stem cells, and totipotent (totally-powerful) cells can differentiate into any kind of cell. When they translate only certain parts of their DNA, they become specialised.
Pluripotent (many-powerful) stem cells can differentiate into a wide variety of tissues, but not quite any whatsoever, like totipotent stem cells.
Multipotent stem cells are yet another sub-branch, narrower than pluripotent stem cells. End-point specialised cells such as heart cells are therefore unipotent and can only propagate their own type.
Stem cells are used in their own right in research to shed light on questions around cell division, differentiation and regulation by testing different culture conditions for different cells at different time points in development to see which transcription factors (which are proteins) are…..