First published online May 12, 2005
Development 132, 1103e (2005)
© The Company of Biologists Limited
Neurogenic timing: a cell-intrinsic matter?
During nervous system development, regulating when progenitor cells stop
proliferating and start differentiating produces the correct number of
neurons. But is neurogenesis triggered by cell-extrinsic or cell-intrinsic
signals? In the developing zebrafish retina it may be primarily the latter,
report Kay and colleagues (see p.
2573). In
Drosophila eye development, signals from newly differentiated neurons
trigger neurogenesis in adjacent progenitors, and researchers have proposed
that a similar sequential induction drives retinal neurogenesis in
vertebrates. By manipulating the environment of developing retinoblasts, Kay
et al show instead that temporally staggered, cell-intrinsic expression of the
proneural gene atonal-homologue 5 (ath5) is sufficient to
support ganglion cell neurogenesis in the zebrafish retina. Thus,
cell-intrinsic factors alone can trigger retinal neurogenesis. However, note
the researchers, midline-derived Sonic hedgehog signals are part of the
mechanism that sets the neurogenic timer earlier in zebrafish development.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
Related articles in Development:
- Staggered cell-intrinsic timing of ath5 expression underlies the wave of ganglion cell neurogenesis in the zebrafish retina
- Jeremy N. Kay, Brian A. Link, and Herwig Baier
Development 2005 132: 2573-2585.
[Abstract]
[Full Text]