First published online August 10, 2007
Development 134, 1701e (2007)
© The Company of Biologists Limited
Axis elongation: flies do it without PCP
Tissue elongation is a general feature of morphogenesis. In vertebrates,
embryonic axis elongation involves cell intercalation and oriented cell
division, processes controlled by the planar cell polarity (PCP) pathway
(which ensures that neighbouring cells adopt the correct polarity in
developing tissues by promoting cell-cell communication). But what about
invertebrate embryos? On p.
3049, Morais da Silva and Vincent report that both processes
contribute to germband elongation (GBE) in Drosophila embryos. The
germband, which forms the larva's trunk, doubles in length during early
embryogenesis. Elongation of the anterior germband involves cell intercalation
but not oriented cell division. By contrast, using time-lapse imaging of
histone-GFP-labelled embryos, the researchers show that mitoses in the
posterior germband are orientated along the axis of elongation during the fast
phase of GBE and that cell division inhibition reduces GBE. This orientation
of cell division, like cell intercalation in the anterior of the germband,
requires segmental patterning, but neither process requires the PCP pathway.
The authors propose, therefore, that an alternative means of planar
polarisation must mediate tissue elongation in Drosophila
embryos.
Related articles in Development:
- Oriented cell divisions in the extending germband of Drosophila
- Sara Morais da Silva and Jean-Paul Vincent
Development 2007 134: 3049-3054.
[Abstract]
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