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Stem Cells to Differentiation
Name: Julianne
Status: Student
Grade: Other
Location: NY
Country: United States
Date: January 2009
Question:
I have a question about stem cell
differentiation. Stem cells can differentiate into many kinds of
cells, including red blood cells, white blood cells, and platelets.
I do not understand how this is possible, as red blood cells do not
have nuclei, while white blood cells do. Does an undifferentiated
stem cell destroy its nucleus in order to become a red blood cell? Does
it create a nucleus to become a white blood cell?
I don't think that a
stem cell can create its own nucleus, knowing that the nucleus is the
"brain" and control center of the cell. I know that you are doing stem
cell research, but maybe you have found the answer to this question
already.
Replies:
All blood cells begin development in the bone marrow although some continue
their development in lymph nodes. The hematopoetic stem cells (blood stem
cells) are found there. Depending on the various cell signals for
differentiation, these stem cells can go on to become any type of blood
cell as needed. If they are to be a white blood cell they keep their
nucleus.
If they are to become a red blood cell, as they develop they
have a nucleus to begin with, but just before they leave the bone marrow
their nucleus disintegrates. This is thought to leave more room for the
cell to have hemoglobin and therefore increase oxygen carrying capacity.
If there is a sudden blood loss and red blood cells leave the bone marrow
more quickly than usual, the nucleus doesn't have time to completely break
down. This can be detected with a special stain and shows up as little
dots in the cytoplasm. These cells are called reticulocytes.
vanhoeck
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Update: June 2012
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