The expression of <it>Gli3</it>, regulated by HOXD13, may play a role in idiopathic congenital talipes equinovarus

Abstract

Abstract Background Idiopathic congenital talipes equinovarus (ICTEV) is a congenital limb deformity. Based on extended transmission disequilibrium testing, Gli-Kruppel family member 3 (Gli3) has been identified as a candidate gene for ICTEV. Here, we verify the role of Gli3 in ICTEV development. Methods Using the rat ICTEV model, we analyzed the differences in Gli3 expression levels between model rats and normal control rats. We used luciferase reporter gene assays and ChIP/EMSA assays to analyze the regulatory elements of Gli3. Results Gli3 showed higher expression levels in ICTEV model rats compared to controls (P Gli3 promoter. The Gli3 promoter also contains two putative Hoxd13 binding sites. Using EMSA, the Hoxd13 binding site 2 was found to directly interact with Hoxd13 in vitro. ChIP assays of the Hoxd13-Gli3 promoter complex from a developing limb confirmed that endogenous Hoxd13 interacts with this region in vivo. Conclusion Our findings suggest that HoxD13 directly interacts with the promoter of Gli3. The increase of Gli3 expression in ICTEV model animal might result from the low expression of HoxD13.