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Identification of spontaneous mutations within the long‐range limb‐specific Sonic hedgehog enhancer ( ZRS ) that alter Sonic hedgehog expression in the chicken limb mutants oligozeugodactyly and silkie breed
Author(s) -
Maas Sarah A.,
Suzuki Takayuki,
Fallon John F.
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.22634
Subject(s) - zone of polarizing activity , sonic hedgehog , limb development , biology , enhancer , limb bud , mutant , ectopic expression , hedgehog , microbiology and biotechnology , gene , genetics , gene expression , ectoderm , embryonic stem cell
The evolutionarily conserved, non‐coding ∼800‐base‐pair (bp) zone of polarizing activity (ZPA) regulatory sequence ( ZRS ) controls Shh expression in the posterior limb. We report that the chicken mutant oligozeugodactyly ( ozd ), which lacks limb Shh expression, has a large deletion within the ZRS . Furthermore, the preaxial polydactylous, Silkie Breed chicken, which develops ectopic anterior limb Shh expression, has a single bp change within the ZRS . Using an in vivo reporter assay to examine enhancer function in the chick limb, we demonstrate that the wild‐type ZRS drives β‐galactosidase reporter expression in the ZPA of both wild‐type and ozd limbs. The Silkie ZRS drives β‐galactosidase in both posterior and anterior Shh domains in wild‐type limb buds. These results support the hypothesis that the ZRS integrates positive and negative prepatterned regulatory inputs in the chicken model system and demonstrate the utility of the chicken limb as an efficient genetic system for gene regulatory studies. Developmental Dynamics 240:1212–1222, 2011. © 2011 Wiley‐Liss, Inc.