Figure 5.

Model depicting the cis-regulatory network underlying Gli-mediated limb patterning. Links with orange diamonds below signify regions tested in for expression in transgenic mice. Interactions between Gli3 and several anteriorly localized genes are depicted at the top of the diagram, with dashed lines and blue diamonds to indicate their speculative nature. Gremlin gene expression is regulated by both anterior and posterior inputs; this continuum of gene expression is represented as discrete enhancer circuits in the anterior and posterior compartments.