Sci. STKE, 15 June 2004
DEVELOPMENT I'm All Thumbs
Studies of tetrapods have identified several of the factors that participate in vertebrate limb patterning. A major player in limb development, Sonic hedgehog (Shh), has a key function in organizing limb asymmetry, such as the difference between the thumb and index finger. Zákány et al. (see the Perspective by Deschamps) examined the genetic cascade leading to anterior-posterior polarity of the vertebrate limb. Early posterior Hox gene expression triggers Shh activation, which in turn induces a second phase of Hox gene expression in a posterior domain. Thus, Hox genes act both early and late in establishing anterior-posterior asymmetry of the limb by acting upstream and downstream of Shh signaling.
Citation: I'm All Thumbs. Sci. STKE 2004, tw217 (2004).
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