Dact gene expression profiles suggest a role for this gene family in integrating Wnt and TGF-β signaling pathways during chicken limb development

Dev Dyn. 2014 Mar;243(3):428-39. doi: 10.1002/dvdy.23948. Epub 2013 May 11.


Background: Dact gene family encodes multifunctional proteins that are important modulators of Wnt and TGF-β signaling pathways. Given that these pathways coordinate multiple steps of limb development, we investigated the expression pattern of the two chicken Dact genes (Dact1 and Dact2) from early limb bud up to stages when several tissues are differentiating.

Results: During early limb development (HH24-HH30) Dact1 and Dact2 were mainly expressed in the cartilaginous rudiments of the appendicular skeleton and perichondrium, presenting expression profiles related, but distinct. At later stages of development (HH31-HH35), the main sites of Dact1 and Dact2 expression were the developing synovial joints. In this context, Dact1 expression was shown to co-localize with regions enriched in the nuclear β-catenin protein, such as developing joint capsule and interzone. In contrast, Dact2 expression was restricted to the interzone surrounding the domains of bmpR-1b expression, a TGF-β receptor with crucial roles during digit morphogenesis. Additional sites of Dact expression were the developing tendons and digit blastemas.

Conclusions: Our data indicate that Dact genes are good candidates to modulate and, possibly, integrate Wnt and TGF-β signaling during limb development, bringing new and interesting perspectives about the roles of Dact molecules in limb birth defects and human diseases.

Keywords: Dact; Dapper; Frodo; Sox9; TGF-β; Wnt; appendicular skeleton; cartilage; chicken embryo; chondrogenesis; digit blastema; digit morphogenesis; joint; limb; limb evolution; perichondrium; tendon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis*
  • Animals
  • Avian Proteins / biosynthesis*
  • Chick Embryo
  • Gene Expression Regulation, Developmental / physiology*
  • Hindlimb / cytology
  • Hindlimb / embryology*
  • Humans
  • Nuclear Proteins / biosynthesis*
  • Synovial Membrane / cytology
  • Synovial Membrane / embryology
  • Transforming Growth Factor beta / metabolism*
  • Wnt Signaling Pathway / physiology*


  • Adaptor Proteins, Signal Transducing
  • Avian Proteins
  • Nuclear Proteins
  • Transforming Growth Factor beta