Cell differentiation Flashcards
What is cell differentiation?
Process by which a cell becomes a more specialized cell type
How does differentiation happen if every cell contains the same DNA?
Differential gene expression
How does differential gene expression happen at the DNA level?
Differences in transcription
Histone modifications
Condensation or loosening the DNA packaging
Enhancers
How does differential gene expression happen at the RNA level?
Post-transcriptional modifications
Alternative splicing
RNA stability
How does differential gene expression happen at the protein level?
Post-translational modifications
Stability
Localization
What is the most common regulatory point for differential gene expression?
Transcription. To transcribe or not to transcribe
How do the correct transcription factors for differential gene expression get expressed?
In response to signalling pathways
What are transcription factors?
Proteins that bind to DNA and regulate gene expression in different combinations at different times
When does most cell differentiation occur?
During development
Does cell differentiation occur in an adult organism?
Yes, mostly to repair damaged tissues
What is a cell lineage?
Pattern of mitotic cell divisions that leads to the formation of specific cell types, tissues, and organs
What controls a cell’s lineage?
Internal and external signals
How do signalling pathways determine a cell lineage?
Signals will induce specific protein expression and localization to cause a cell to become a certain cell type
What cells form the beginning of a cell lineage?
Stem cells
What are stem cells?
Unspecialized cells that have the ability to reproduce to create more of themselves, or to differentiate into more specialized cell types
What is symmetric division?
The two daughter cells produced are identical to each other. Either 2 stem cells or two differentiated cells are produced
What is asymmetric division?
The two daughter cells produced are different from each other
How do asymmetric divisions happen?
Certain proteins will accumulate in one side of the parent cell, and when it divides those proteins are only in 1 daughter cell
What is cell potency?
The ability for a cell to become something else
How are adult stem cells different from embryonic stem cells?
Adult stem cells are multipotent and don’t have all the ethical considerations that ESCs do. ESCs are also pluripotent
How does potency change further along a cell lineage?
Less become less potent. They start out totipotent in the early embryo, then become pluripotent for development, then become multipotent later on and in the adult
What are progenitor cells?
The cells that come before the final differentiation
What is a stem cell niche?
A location in an adult organism where a population of stem cells can be maintained
Where is the stem cell niche in the intestines? Why is this stem cell population needed?
Located between the vili in the crypts. Intestinal epithelial cells are constantly dying and getting sluffed off, so they need to be constantly replaced
