Methods: In this study, immunohistochemical staining was performed on developmentally staged mouse molar tooth buds (E12.5, E14.5, E16.5, and P1) using antibodies against three phosphorylated pRb (ppRb) isoforms - ppRbS780, ppRbS795, and ppRbS807/811. Co-localization of individual ppRb isoforms and phospho-histone H3, a marker indicating cell cycle progression, was analyzed by double IF staining of developmentally staged mouse molar buds and P1 incisors.
Results: Our results revealed distinct developmental expression patterns for individual ppRb isoforms in differentiating dental epithelial and dental mesenchymal cells. Most interestingly, ppRbS807/811 was only detected in the nuclei of pre-ameloblasts and not at all in differentiated ameloblasts, and in the cytoplasm and nuclei of differentiated odontoblasts, but not in pre-odontoblasts.
Conclusions: Our results suggest that each of the three pRb isoforms examined in this study may have discrete functions in tooth development.
Keywords: Cell biology, Gene expression, Growth & development, Oral biology and Retinoblastoma protein