Regulation of leg size and shape: Involvement of the Dachsous fat signaling pathway
How limb size and shape is regulated is a long standing question in developmental and regeneration biology. Recently, the protocadherin Dachsous Fat (Ds Ft) signaling pathway has been found to be essential for wing development of the fly and leg regeneration of the cricket. The Ds Ft signaling pathway is linked to the Warts Hippo (Wts Hpo) signaling pathway, leading to cell proliferation. Several lines of evidence have suggested that the Wts Hpo signaling pathway is involved in the control of organ size, and that this pathway is regulated by Ds Ft and Merlin Expanded, which are linked to morphogens such as decapentaplegic/bone morphogenic protein, Wingless/Wnt, and epidermal growth factor. Here we review recent progress in elucidating mechanisms controlling leg size and shape in insects and vertebrates, focusing on the Ds Ft signaling pathway. We also introduce a working model, Ds Ft steepness model, to explain how steepness of the Ds Ft gradient controls leg size along the proximodistal axis. Developmental Dynamics 240:1028 1041, 2011. (c) 2011 Wiley Liss, Inc.
Developmental dynamics an official publication of the American Association of Anatomists