STAGE-SPECIFIC EXPRESSION OF DECAPENTAPLEGIC-VG-RELATED GENE-2, GENE-4, AND GENE-6 (BONE MORPHOGENETIC PROTEIN-2, PROTEIN-4, AND PROTEIN-6)DURING HUMAN TOOTH MORPHOGENESIS

Members of the decapentaplegic-Vg-related (DVR) gene family are diffus ible signaling molecules regulating inductive tissue interactions duri ng vertebrate development. Expression of DVR/bone morphogenetic protei n (BMP) 2, 4, and 6 was studied in human fetal teeth. Sequential morph ogenetic stage-specific studies of DVR/BMP 2 and 4 mRNA expression by in situ hybridization revealed transcripts for DVR/BMP 4 during compac tion of the dental mesenchyme. In contrast, DVR/BMP 2 mRNA appeared la ter during tooth development and was located in differentiated cells ( odontoblasts). These results were confirmed by reverse-transcription p olymerase chain reaction (RT-PCR), which detected DVR/BMP 2 and 4 mRNA in human tooth-germ samples. DVR/BMP 6 protein was distributed in the early dental epithelium and, later, in pre-odontoblasts and odontobla sts, where it remained during dentin formation. These results suggest that DVR/BMP 4 is involved in the early tooth morphogenesis. DVR/BMP 6 may, in particular, be implicated in epithelial-mesenchymal interacti ons controlling cytodifferentiation. DVR/BMP 2 and 6 may also be invol ved in odontoblast secretory function. The results suggest that member s of the DVR gene family may play regulatory roles during human tooth development.