Question

Working with neurons in the lab, you noticed that a batch of isolated neurons from Science Express is not working appropriately. Your research advisor asks you to sort it out. Doing several experiments you noticed that most neurons either failed to start or failed to get back to the resting phase (state). You suspect that the special batch of neurons might carry a mutation and was mistakenly sent by this company. What kind of mutation do you suspect these neurons carry? Include in your discussion how to process would work for wild type neurons.

Answer 1

If your cells fail to enter G0 phase, this means they keep dividing uncontrollably. However, by the way the question is posed, it would seem tht they are initially in G0, then you induce division (common for cell culture, I assume), and then you are not able to halt it. This has Tumor Suppressor Genes written all over it.

The Tumor suppresors (TSG, for short) have the task of halting and resuming cell cyle at certain stages. P53 and Rb proteins are the flagships of TSGs, being in charge of stopping division to check for errors in the new DNA strands or to cause quiescence in mature and stem cells. Your cells probably contain a mutated P53 or Rb gene (or both), which results in them not being able to stop dividing and thus, will never enter the G0 phase. To test this hypothesis you can extrat DNA and sequence using primers for the P53/Rb gene and see if they are mutated.

I am not quite sure of what you are trying to ask in the second qustion, but I will assume it is about how the process of entering G0 happens in regular (Wild Type) neurons, and it is quite simple:

Neurons are a type of cell that does not divide, safe for a few neurogenic sports in the brain. This means that, once they are mature, fully differentiated cells, they will enter G0 and stay that way until they die. In a culture, neurons should divide until they are fully differentiated, which I assume is what yu expect for these experiments, and then stop dividing.