Developmental stalling and organ-autonomous regulation of morphogenesis.

Timing of organ development during embryogenesis is coordinated such that at birth, organ and fetal size and maturity are appropriately proportioned. The extent to which local developmental timers are integrated with each other and with the signaling interactions that regulate morphogenesis to achieve this end is not understood. Using the absolute requirement for a signaling pathway activity (bone morphogenetic protein, BMP) during a critical stage of tooth development, we show that suboptimal levels of BMP signaling do not lead to abnormal morphogenesis, as suggested by mutants affecting BMP signaling, but to a 24-h stalling of the intrinsic developmental clock of the tooth.