Expression patterns of histone acetyltransferases p300 and CBP during murine tooth development.

The transcription coactivators p300 and CBP were reported to have indispensable roles in various tissues during the embryonic and fetal stages. Little is known about the activities of these coactivators during the tooth development, so we investigated the temporal expression patterns of p300 and CBP in developing mouse tooth germs. The first molars of fetal BALB/c mice were used to investigate p300 and CBP expression patterns. Immunohistochemistry was performed on a series of sections from embryonic Day (E) 11.5 to E19.5. Laser microdissection and real-time polymerase chain reactions were used to investigate the inner enamel epithelium, stellate reticulum, outer enamel epithelium, and dental papilla between E18.5 and E19.5. P300 had a presence in nearly every region of the tooth germ from E11.5 to E19.5. However, the expression of CBP was first detected at E12.5 and was relatively lower than the expression of p300 until E18.5. Both p300 and CBP expression levels peaked unexpectedly on Day E18.5. Additionally, the expression of p300 was distinctly lower than CBP at E19.5. In the late bell stage, p300 and CBP mRNA was highly expressed in the stellate reticulum and dental papilla, and there was a relatively low amount of CBP mRNA in the outer enamel epithelia and inner enamel epithelia from E18.5 to E19.5. The temporal patterns of p300 and CBP expression were identified during tooth development. The difference in the spatiotemporal expression of p300 and CBP indicated that they play different roles in tooth development.