Could anyone in this forum explain the difference between cell autonomous and cell non-autonomous to me? I looked up these two terms online, but still can not totally get the difference between them. Can anyone give me an example of them? Thank you!
A cell-autonomous mutation affects only those cells that contain the mutation. Non-cell-autonomous means that the mutation affects cells that do not contain the mutation (e.g., if the mutation affects a secreted ligand, then the target cells could be non-mutant but still be affected). The term is sometimes applied to non-mutant conditions, such as RNAi spreading phenomena that function non-autonomously.
I guess I would choose different phrasing than Sperm or Egg?:
Questions of cell-autonomy usually arise in signaling during development of a cell / tissue or in a behavior, for example if you find a mutant that is uncoordinated. This could be due to a developmental failure of the neurons (neurons fail to make proper synapses with muscle), or it could be due to a lack of signaling that allows locomotion (neurons are morphologically intact, but cannot release neurotransmitter). Since the mutation is almost always present in all cells of the animal, pinning down where the observed defect arises can be very difficult. If the defect in the function of the neurons is caused by a failure in those specific neurons, it is cell-autonomous. An example would be a neural transcription factor that is required for development or maturation of the neurons. You can generally show this by trying to re-express the wild type gene back in those neurons or show through mosaic analysis that loss of the gene in neurons causes the defect.
If instead the mutation is blocking a signal from another tissue (e.g. muscle or skin), that is preventing these otherwise normal neurons from finishing development, that gene is said to function non-cell autonomously. An example would be some guidance molecule, expressed on muscle or hypodermis, that is required for the neuron to develop or acquire its mature function. You may be able to rescue this defect by re-expressing the gene in those cells but not neurons. If two neurons make synapses with each other to achieve a behavior, you would need to determine whether the defect is due to function in the presynaptic or postsynaptic cell (or both), again through some kind of rescue in one but not the other approach.