Analysis of Nedd4 expression during skeletal development in the mouse limb

Nedd4, a ubiquitin-protein ligase, was originally identified as being down- regulated during development of the mouse brain (Nedd denotes neural precur sor cell expressed developmentally down-regulated) (Kumar, S., Tomooka, Y., Noda, M., 1992. Identification of a set of genes with developmentally down -regulated expression in the mouse brain. Biochem. Biophys. Res. Commun. 18 5, 1155-1161). Subtractive hybridization was used in an attempt to identify genes that are preferentially expressed early in skeletogenesis. Using thi s technique Nedd4 was identified multiple times. Northern blot analysis con firmed that Nedd4 is down-regulated in the forelimb anti hind limb. In situ hybridization was carried out to identify regions of the limb bud expressi ng Nedd4. Nedd4 is expressed weakly in condensing mesenchyme, and abundantl y in proliferating and prehypertrophic chondrocytes, but is undetectable in hypertrophic chondrocytes. Primary cultures, which closely mimic in vivo c hondrogenesis, were also used to demonstrate the stage-specific expression of Nedd4 during early skeletal development. (C) 2000 Elsevier Science Irela nd Ltd. All rights reserved.