First published online October 30, 2006
Development 133, 2205e (2006)
© The Company of Biologists Limited
Planar polarity: a radical rethink
Planar cell polarity (PCP) - asymmetry in the plane of epithelial tissues -
controls the arrangement of structures such as insect hairs and ommatidia. The
prevailing model for PCP establishment in Drosophila proposes that a
morphogen gradient organizes the expression of two atypical cadherins,
Dachsous (Ds) and Fat (Ft), and of the Golgi protein Four-jointed, to set up
Ds system gradients. These then act via the Stan system - the cadherin
receptor-like molecule Starry Night (Stan) and the Wnt receptor Frizzled (Fz)
- to orientate hairs and ommatidia. On
p. 4561, José
Casal, Peter Lawrence and Gary Struhl challenge this model by reporting that
the Ds and Stan systems act independently to orientate abdominal hairs. For
example, they show that ectopic expression of ds repolarizes
surrounding cells even in flies that lack both Stan and Fz. Other experiments
indicate that cells that send polarity information need either Ds or Ft but
responding cells need both proteins. From these findings, the researchers
propose a radical new model that suggests how Ds-Ft bridges between cells
might propagate PCP.
Related articles in Development:
- Two separate molecular systems, Dachsous/Fat and Starry night/Frizzled, act independently to confer planar cell polarity
- José Casal, Peter A. Lawrence, and Gary Struhl
Development 2006 133: 4561-4572.
[Abstract]
[Full Text]
