Expression of Scube genes during murine tooth development

Objectives: Teeth are organs that form in the embryo from a series of interactions between oral epithelium and neural crest-derived ectomesenchyme of the early jaws. Scube (Signal peptide-CUB-EGF domain-containing protein) genes encode a three-family group of secreted plasma membrane-associated proteins. Members of this family share a conserved protein domain organization of at least five recognizable motifs: an N-terminal signal peptide sequence, multiple EGF domains, a large spacer region followed by three repeated stretches of 6-cysteine residues and a C-terminal CUB domain. This study was conducted to evaluate the expression pattern of Scube1 and Scube3 during mouse tooth development. Methods: Radioactive section in situ hybridization using 35S-UTP radio-labelled riboprobes. Results: Scube1 and -3 demonstrate distinct and reciprocal expression patterns in the developing tooth. Scube1 expression is restricted to the mesenchymal component of the tooth from the early bud stage of development, with transcripts localizing to the dental papilla during the cap and bell stages of development. In contrast, Scube3 expression is restricted to the epithelial component of the developing tooth germ and is present throughout the primary thickening during initiation and inferior regions of the tooth bud. During the cap stage, transcripts are restricted to the internal and external enamel epithelium in peripheral regions of the tooth germ, but absent from the stellate reticulum internally. Conclusion: Scube1 and Scube3 expression patterns are highly restricted and reciprocal during murine tooth development. These patterns of expression suggest that Scube-family genes may play an important role during tooth development. Supported by the Programme Alâan, the European Union Programme of High Level Scholarships for Latin America (E07D400355BR).