First published online February 2, 2004
Development 131, 403e (2004)
© The Company of Biologists Limited
Cue motoneurone development
In the vertebrate nervous system, specialised cell types develop at
characteristic positions. To investigate how the fine patterning of
motoneurone subtypes is specified, Lewis and Eisen turned to zebrafish embryos
in which three subtypes of primary motoneurones (PMNs) occur in a segmentally
reiterated pattern along the spinal cord (see
p. 891). Two of these
PMN subtypes - middle primary (MiP) and caudal primary (CaP) - can be
identified molecularly and by their axonal trajectories, i.e. by which tissue
they innervate. Lewis and Eisen report that in zebrafish mutants that lack the
overlying paraxial mesoderm, PMNs adopt a gene expression profile that has
characteristics of both MiPs and CaPs. Furthermore, in mutants with severely
disrupted paraxial mesoderm, although the PMNs have a hybrid gene expression
profile, their axonal trajectories resemble those of CaP motoneurones. These
results are consistent with the hypothesis that signals from the paraxial
mesoderm specify the segmental pattern of PMN subtype identity in
zebrafish.
Related articles in Development:
- Paraxial mesoderm specifies zebrafish primary motoneuron subtype identity
- Katharine E. Lewis and Judith S. Eisen
Development 2004 131: 891-902.
[Abstract]
[Full Text]
