Abstract
Rb1 is a tumor suppressor gene that regulates cell cycle progression through interactions with E2F transcription factors. In recent years, new roles for Rb1 in regulating cellular differentiation have also emerged. For example, it has been shown that Rb1 regulates osteoblast differentiation in a cell cycle independent manner, by binding to the transcription factor Runx2, and facilitating the up-regulation of late bone differentiation markers. Based on the facts that Runx2 also functions in tooth development, and that little is known about potential roles for Rb1 in mammalian tooth development, here we evaluated the expression of Rb1 mRNA in developmentally staged mouse teeth. Our data show that Rb1 mRNA is expressed in both dental epithelial and dental mesenchymal progenitor cells. In addition, Rb1 mRNA appears upregulated in differentiating ameloblasts and odontoblasts, suggesting roles for Rb1 in tooth differentiation.