Highly regulated expression of subtilisin-like proprotein convertase PACE4(SPC4) during dentinogenesis

Expressions of mRNAs for four subtilisin-like pro-protein convertases (SPCs : furin, PACE4, PC6, and PC8) and bone morphogenetic protein 4 (BMP4) in th e rat molar tooth during development were analyzed by Northern blotting, re verse transcriptase-polymerase chain reaction (RT-PCR), and in situ hybridi zation to explore the possible involvement of SPCs in the processing of pro BMPs. We found a temporospacial expression of PACE4, but not one of the oth er SPCs, in this tissue; i.e., RT-PCR analysis revealed that the level of P ACE4 mRNA, but not that of the other SPC mRNAs became high around the secon d postnatal day. This increase was in good accordance with the increase in BMP4 mRNA, indicating an apparent association of these molecules with the d ifferentiation and establishment of functional ameloblasts and odontoblasts . During dentinogenesis, PACE4 mRNA was localized in the ameloblasts and od ontoblasts. These observations suggest that PACE4 plays a crucial role in d entinogenesis, especially via the activation of BMPs. (C) 2000 Academic Pre ss.