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Single base pair change in the long‐range Sonic hedgehog limb‐specific enhancer is a genetic basis for preaxial polydactyly
Author(s) -
Maas Sarah A.,
Fallon John F.
Publication year - 2005
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.20254
Subject(s) - sonic hedgehog , enhancer , biology , limb development , polydactyly , zone of polarizing activity , transcription factor , anatomy , limb bud , gli3 , genetics , microbiology and biotechnology , gene , embryonic stem cell , mesoderm , repressor
Abstract In most instances of preaxial polydactyly (PPD), Sonic Hedgehog ( Shh ), an essential limb patterning signal, is ectopically expressed in an anterior region of the developing limb in addition to the normal posterior domain. It is thought that this anterior Shh expression leads directly to the development of the extra digits. Recent reports have identified a conserved limb‐specific Shh enhancer ∼1 megabase upstream of the Shh transcription initiation site, and individual base pair changes within this region are associated with PPD. We report here that a single base pair change within this enhancer is sufficient to drive β‐galactosidase expression in both anterior and posterior limb domains, similar to Shh expression in animal PPD models, whereas a wild‐type construct is expressed only in the posterior limb, similar to Shh expression in normal embryos. These findings provide the first direct evidence that a single base pair change within the limb‐specific Shh enhancer acts as a genetic basis for PPD. Developmental Dynamics 232:345–348, 2005. © 2005 Wiley‐Liss, Inc.