Journal of Neuroscience, Vol 15, 7879-7891, Copyright © 1995 by Society for Neuroscience
Fibroblast growth factor 2 increases Otx2 expression in precursor cells from mammalian telencephalon
L Robel, M Ding, AJ James, X Lin, A Simeone, JF Leckman and FM Vaccarino
Child Study Center, Yale University, New Haven, Connecticut 06520, USA.
Dissociated primary cultures from rat telencephalon at different
developmental stages were used to study the effect of basic fibroblast
growth factor (FGF2) on Otx2, Dlx1, and Emx1, three homeobox genes
expressed in different regions of the developing mammalian forebrain. At
embryonic day (E)13.5. the regional pattern of expression of Otx1, Otx2,
Dlx1, Dlx2, Dlx5, and Emx1 is maintained in primary culture, suggesting
that cells are already committed to a regional identity at this stage. In
these cultures, Otx2 is expressed by precursor cells, whereas Dlx1 and Emx1
are predominantly expressed by postmitotic cells. We found that FGF2
increased Otx2 expression within precursor cells and the total number of
Otx2-expressing cells. This effect was gene- specific, dose-dependent, and
temporally regulated, with larger effects at earlier stages of development
(E11.5). At E13.5, the effect of FGF2 on Otx2 expression was restricted to
the basal telencephalon. Our results suggest that a restricted population
of neuroblasts respond to FGF2 in a temporally regulated fashion by
proliferating and increasing Otx2 expression. This interaction between FGF2
and Otx2 may be important for the regulation of neurogenesis in the
forebrain.
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