Conservation of dishevelled structure and function between flies and mice: isolation and characterization of DvZ2

The segment polarity gene dishevelled (dsh) of Drosophila is required for pattern formation of the embryonic segments and the adult imaginal discs. dsh encodes the earliest-acting and most specific known component of the signal transduction pathway of Win-gless, an extracellular signal homologous to Wntl in mice. We have previously described the isolation and characterization of the Dvll mouse dsh homolog. We report here the isolation of a second mouse dsh homolog, Dv12, which maps to chromosome 11. The DvZ2 amino acid sequence is equally related to the dsh sequence as is that of Dvll, but Dv12 is most similar to the Xenopus homolog X&h. However, unlike the other vertebrate &I homologs. Like the other genes, Dv12 is ubiquitously expressed throughout most of embryo-genesis and is expressed in many adult organs. We have developed an assay for dsh function in fly embryos, and show that Dv12 can partially rescue the segmentation defects of embryos devoid of dsh. Thus, Dv12 encodes a mammalian homolog of dsh which can trans-duce the Wingless signal