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neurogenesis marker timecourses

From here:

 

All cell types within the body express different genes/proteins that serve the cell’s function. Since a muscle cell has a completely different function than a skin cell, it will naturally express different proteins. In like manner, a 1 week-old neuron is functionally distinct from a 4 week-old neuron and the two will also express different proteins (to some extent). Many people have taken advantage of this, using these different proteins as markers that identify a new cell as a neuron vs. a glial cell or, more specifically, an immature neuron vs. a mature neuron. By simultaneously visualizing (via immunohistochemistry) both the birthdating marker (e.g. BrdU) and these phenotypic markers, one can know both the exact age of the neuron and its general degree of maturity. For a 10 sec guide to cell labeling with BrdU and phenotypic markers, see here.

 

What do these expression timecourses tell us?

 

some markers (proteins) are increasingly expressed as new neurons mature over 4 weeks (NSE, NeuN, calbindin)

other markers are mainly expressed when new neurons are < 4 weeks-old (DCX, PSA-NCAM, calretinin)

most studies have used the same markers (e.g. DCX, NeuN) to simply demonstrate that new cells are neurons, but some have examined expression of markers that are associated with a more specific function, such as glucocorticoid receptors (Cameron 1993, Garcia 2004) or vascular markers (Palmer 2000)

BrdU (or other birthdating markers) labeled cells express cell division markers (e.g. Ki67) several days after BrdU is administered. This does not mean newborn neurons are dividing – what it represents is the continued division of the stem cell, or precursor cell, that was originally labelled. (therefore you can never know the exact age of a new cell, but pretty close)

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Uploaded on February 28, 2010
Taken on March 7, 2010