M. Tanaka et al., Notch2 expression negatively correlates with glial differentiation in the postnatal mouse brain, J NEUROBIOL, 41(4), 1999, pp. 524-539
Notch family molecules are thought to be negative regulators of neuronal di
fferentiation in early brain development. After expression in the embryonic
period, Notch2 continues to be expressed postnatally in the specific regio
ns in the rodent brain. Here, we examined Notch2 expression in the postnata
l mouse brain using lacZ knockin animals at the Notch2 locus. Notch2 expres
sion was observed in the developing cerebellum and hippocampus characterist
ic regions where neurogenesis persists after birth. Double staining of sect
ions revealed that Notch2 was expressed by Bergmann glia in the cerebellum,
radial glia in the hippocampus, and some astrocytes in both regions. Notch
2 expression by glial cells was clearly confirmed in dissociated cell cultu
res. Interestingly, neocortical glia, many of which did not express Notch2
in vivo, did express Notch2 in a dissociated culture condition. The triple
staining of dissociated cell cultures revealed that stronger Notch2 express
ion correlated with the immature type of glial gene expressions: stronger v
imentin and weaker glial fibrillary acidic protein expressions, In addition
, Notch2 expression correlated with the incorporation of bromode-oxyuridine
both in vivo and in vitro. Thus, these findings demonstrate that Notch2 is
expressed not only by neuronal cells in the embryonic brain, but also by g
lial cells in the postnatal brain, and that its expression negatively corre
lates with glial differentiation, proposing its novel function as a negativ
e regulator of glial differentiation in mammalian brain development. (C) 19
99 John Wiley & Sons, Inc.