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Pleiotropic patterning response to activation of Shh signaling in the limb apical ectodermal ridge
Author(s) -
Wang ChiKuang Leo,
Tsugane Mizuyo H.,
Scranton Victoria,
Kosher Robert A.,
Pierro Louis J.,
Upholt William B.,
Dealy Caroline N.
Publication year - 2011
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.22628
Subject(s) - apical ectodermal ridge , biology , zone of polarizing activity , limb bud , limb development , microbiology and biotechnology , anatomy , ectoderm , ectodermal dysplasia , ridge , genetics , embryo , embryogenesis , paleontology
Sonic hedgehog (Shh) signaling in the limb plays a central role in coordination of limb patterning and outgrowth. Shh expression in the limb is limited to the cells of the zone of polarizing activity (ZPA), located in posterior limb bud mesoderm. Shh is not expressed by limb ectoderm or apical ectodermal ridge (AER), but recent studies suggest a role for AER–Shh signaling in limb patterning. Here, we have examined the effects of activation of Shh signaling in the AER. We find that targeted expression of Shh in the AER activates constitutive Shh signaling throughout the AER and subjacent limb mesoderm, and causes a range of limb patterning defects with progressive severity from mild polydactyly, to polysyndactyly with proximal defects, to severe oligodactyly with phocomelia and partial limb ventralization. Our studies emphasize the importance of control of the timing, level and location of Shh pathway signaling for limb anterior–posterior, proximal–distal, and dorsal–ventral patterning. Developmental Dynamics 240:1289–1302, 2011. © 2011 Wiley‐Liss, Inc.