In an embryo, the stem cells develop into specific organs under the influence of complex extracellular signals. Sonic hedgehog (Shh) plays an important role in this process but its signalling pathway is not entirely understood. In August 31 Science Gurtej Dhoot and colleagues from the University of Pennsylvania Medical Center identify a member of a family of conserved sulfatases, QSulf1, which is responsive to Shh signaling and has role in embryonic cell fate determination.

Dhoot et al. identified QSulf1 via a molecular cloning screen for Shh responsive genes activated during somite formation in quail embryos. They found that QSulf1 expression is required for the activation of MyoD, a specific (Wnt) induced regulator of muscle specification. QSulf1 is localized on the cell surface and regulates heparan-dependent Wnt signaling in myogenic progenitor cells through a mechanism dependent on the catalytic activity of the molecule (Science 2001, 293:1663-1666).

Identifying...