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Bone Morphogenetic Protein (BMP) signaling is essential for craniofacial development, though little is known about the mechanisms that govern BMP secretion. We show that depolarization induces calcium-dependent BMP4 release from mouse embryonic palate mesenchyme. We show endogenous transient changes in intracellular calcium occur in cranial neural crest cells, the cells from which embryonic palate mesenchyme derives. Waves of transient changes in intracellular calcium suggest that these cells are electrically coupled and may temporally coordinate BMP release. These transient changes in intracellular calcium persist in palate mesenchyme cells from embryonic day 9.5 to 13.5 mice. Disruption of a potassium channel called Kcnj2 significantly decreases the amplitude of calcium transients and the ability of cells to secrete BMP. Kcnj2 knockout mice have cleft palate and reduced BMP signaling. Our data suggest that temporal control of developmental cues is regulated by ion channels, depolarization, and intracellular calcium for mammalian craniofacial morphogenesis.
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Development of the Jaws and Teeth in Mouse Lemurs
ABSTRACT Rodent models have provided a detailed body of knowledge on craniodental development. Yet, it is unknown how well altricial mammals such as mice parallel primate and specifically human craniodental development. To address this, here we document the ontogeny of jaw‐related structures in a cross‐sectional prenatal sample of mouse lemurs (Microcebusspp.). Mouse lemurs follow the same developmental sequence as humans and mice with respect to the earliest appearance of jaw structures. Meckel's cartilage forms before any membranous bone of the mandibular body; mandibular basal bone begins to ossify before teeth enter the bud stage. Lower jaw structures commence morphogenesis before the corresponding maxillary elements. The basal bone of both jaws becomes more complex in larger fetuses. As tooth germs mature, the follicle—a supporting connective tissue outside the papilla and enamel organ—matures into a cellular, loosely fibrous tissue. Surrounding the follicle is a sheet‐like connective tissue, theepifollicular membrane. In tooth germs reaching the bell stage, alveolar bone forms within this membrane. One subtle distinction of mouse lemurs to prior descriptions of fetal anthropoids is the lemur's faster maturation of the deciduous canine compared to incisors, the reverse of the anthropoid pattern. However, broadly it appears that all primates studied thus far have a very prolonged duration of dental maturation, which continues long after other facial elements (e.g., hard palate) are fully formed. This scenario contrasts with altricial rodents, in which palate formation occurs near parturition, and only a day before the first permanent molar reaches the bell stage.
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- PAR ID:
- 10674227
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- American Journal of Primatology
- Volume:
- 88
- Issue:
- 3
- ISSN:
- 0275-2565
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/ajp.70131
