Journal of Neuroscience, Vol 5, 3302-3309, Copyright © 1985 by Society for Neuroscience
The influence of neural tube-derived factors on differentiation of neural crest cells in vitro. I. Histochemical study on the appearance of adrenergic cells
MJ Howard and M Bronner-Fraser
The neural crest gives rise to numerous derivatives including adrenergic
and cholinergic neurons, supportive cells of the nervous system, and
melanocytes. In tissue culture, neural crest cells explanted from both
cranial and trunk regions were found to differentiate into adrenergic
neuroblasts or into pigmented cells when grown in medium containing 10%
chick embryo extract. When the embryo extract concentration was lowered to
2%, no catecholamine-containing cells (as assayed by formaldehyde-induced
fluorescence) were detected, although pigment cells were observed. These
results suggest the presence of a factor(s) in embryo extract that promotes
or supports adrenergic differentiation. To examine the possible tissue
sources of this factor(s), neural tube, notochord, or somite cells were
used to condition medium containing 2% embryo extract. When neural crest
cells were grown in medium conditioned by neural tube cells, adrenergic
neuroblasts were observed in all cultures. However, somite- and notochord
conditioned medium did not support adrenergic differentiation. In addition,
medium supplemented with extracts derived from central nervous system
components did support adrenergic expression, whereas medium supplemented
with embryo extract from which the neural tissue was removed did not.
Direct contact with neural tube cell ghost membranes was unable to
substitute for high embryo extract concentrations or for neural
tube-conditioned medium. These results suggest that the neural tube makes a
diffusible factor(s) that will support adrenergic differentiation of neural
crest cells.
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