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How Do Cells Know What Genes Are Defective Or Damaged?

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Posted on Tue, 21 Oct 2014
Question: Academic question. Cells are able to repair. How do cells know what genes are defective or damaged and how do cells know what the gene was before it became damaged or defective? Is there immune system cells that have a copy of the DNA before it was damaged or defective or epigenetically changed?
doctor
Answered by Dr. Prakash H Muddegowda (26 minutes later)
Brief Answer:
P53 - Master control gene

Detailed Answer:
Hi,
Thanks for asking.
I am Dr. Prakash HM and I will be answering your query.

As every cell divides to form new cells, they undergo a phase of cell cycle. Each cell cycle has a certain check before any cell division. During this check phase, the cell is evaluated for its DNA damage (P53 is controlling gene). If damaged, further progression is blocked and is sent for repair or cell death depending upon the amount of DNA damage.

Every stem cell has the same DNA and immune cells (peripheral stem cells only) also have similar DNA. As the cell matures from the stem cell, it differentiates into various cells, performing different functions.

Only the stem cells either during birth (umbilical cord stem cells) or later peripheral blood stem cells can be used to grow new different cells. All cells have same DNA, only neoplastic cells have mutated DNA.

Any further queries, happy to help again.

Dr. Prakash HM
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Prakash H Muddegowda (3 hours later)
So is there interaction between the stem cells and the damaged or defective cells? At what stage is there interaction? During cell division (mitosis) is there interaction?

I found that neoplastic cells are really only different in that the DNA is changed. They go from being stem cells to being cancer stem cells and these cancer stem cells divide asymmetrically, ie the original cancer stem cell divides into itself and a daughter cancer cells. And they generate many, many different types of cancer stem cells and other daughter cells. And I have also been able to change them back to normal tissue cells so the changes would have to be either epigenetic or if there are other changes like frame shifts they are deliberate and reversible.

What puzzles me is that the cells seem to know of their own accord what to do and how to repair or change or to signal their own death. What guides them? How do they know?

I have done my research in this area using insight meditation (Vipassana) and it is hard to see what is going on at the molecular level. I can only see sub-cellular components but not in refined image. There are other cells around and if they do interact then it has to be by signalling between each other. But it still means that a single cell has to know of the millions of amino acid components which ones are faulty. How? Has any science research been done in this area?
doctor
Answered by Dr. Prakash H Muddegowda (12 hours later)
Brief Answer:
Programmed cell death or apoptosis.

Detailed Answer:
Hi,
Thanks for asking again.

1. No, there is no specific interaction between stem cells and damaged cells. Any damaged cell which goes to the cell cycle for cell division (mitosis) is either repaired and put back to cell cycle or it is arrested and put to cell death (apoptosis). Stem cells do not have any role at that position.

2. Neoplastic cells are mutated cells. They have the capacity to proliferate without any stimulus. Each neoplastic cell produces one specific cancer and it keeps on dividing until it runs out of nutrition. Neoplastic cells are irreversible change and they do not return to normal. Treatment can be focused only on killing it. Reversible change is not a part of neoplasia.

3. Cell signaling there own death is called as programmed cell death or apoptosis. There are certain pro and anti-apoptotic genes, which depending on the presence or absence of stimulus to live will activate certain caspases or enzymes, to induce cellular destruction. DNA in every cell is the same, however, each cell has different function to perform and depending on its ability to repair, it will repair or change. If not it undergoes cell death due to apoptosis. If it is not programmed, then it undergoes necrosis (for eg: due to ischemia, chemical or biological injury)

4. Studies are ongoing. DNA in each cell has the knowledge has various regulators. After DNA, RNA regulates then protein production for specific function takes place. You can find plenty of research online specifically in journals.
However, I cannot comment about Vipassana, as I have very limited knowledge about it.

Any other queries, happy to help again.

If you do not have any further queries, you can close the discussion and rate the answer.

Dr. Prakash HM
Note: For detailed guidance on genetic screening consult a genetics specialist

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Prakash H Muddegowda

Geriatrics Specialist

Practicing since :2004

Answered : 2138 Questions

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How Do Cells Know What Genes Are Defective Or Damaged?

Brief Answer: P53 - Master control gene Detailed Answer: Hi, Thanks for asking. I am Dr. Prakash HM and I will be answering your query. As every cell divides to form new cells, they undergo a phase of cell cycle. Each cell cycle has a certain check before any cell division. During this check phase, the cell is evaluated for its DNA damage (P53 is controlling gene). If damaged, further progression is blocked and is sent for repair or cell death depending upon the amount of DNA damage. Every stem cell has the same DNA and immune cells (peripheral stem cells only) also have similar DNA. As the cell matures from the stem cell, it differentiates into various cells, performing different functions. Only the stem cells either during birth (umbilical cord stem cells) or later peripheral blood stem cells can be used to grow new different cells. All cells have same DNA, only neoplastic cells have mutated DNA. Any further queries, happy to help again. Dr. Prakash HM