Genetic analysis of the vertebrate Hedgehog-signaling pathway using muscle cell fate specification in the zebrafish embryo.

Over the recent years, a large number of embryological studies with the zebrafish have provided substantial evidence of its usefulness for the investigation of the genetic and cellular basis of vertebrate development. With regard to the Hedgehog (Hh) pathway, forward as well as reverse genetic approaches in this organism have not only validated the roles of evolutionarily conserved players of the signaling cascade, but have also contributed to the isolation of several novel components that had remained unidentified through screens in other animal models. Here, the author describes a whole mount antibody labeling method that allows the detection of three unique muscle cell fates in the zebrafish embryo, which are induced by distinct levels and timing of Hh-signaling activity. This technique provides a rapid and convenient assay that can be utilized for the evaluation of effects of loss- or gain-of-function of any gene on the levels of Hh pathway activation during embryogenesis.