The dermis promotes the development and maintains the functional components of skin, such as hair follicles, sweat glands, nerves and blood vessels. The dermis is also crucial for wound healing and homeostasis of the skin. The dermis originates from the somites, the lateral plate mesoderm and the cranial neural crest. Despite the importance of the dermis in the structural and functional integrity of the skin, genetic analysis of dermal development in different parts of the embryo is incomplete. The signaling requirements for ventral dermal cell development have not been established in either the chick or the mammalian embryo. We have shown previously that Wnt signaling specifies the dorsal dermis from the somites. In this study, we demonstrate that Wnt/β-catenin signaling is necessary for the survival of early ventral dermal progenitors. In addition, we show that, at later stages, Wnt/β-catenin signaling is sufficient for ventral dermal cell specification. Consistent with the different origins of dorsal and ventral dermal cells, our results demonstrate both conserved and divergent roles of β-catenin/Wnt signaling in dermal development.

Wnt signaling is critical for proper development of the head and face in the mouse embryo, playing important roles in various aspects of craniofacial development ranging from axis formation to survival of cranial neural crest cells to patterning of the brain. The signaling requirements for the development of different cell lineages in the head and face are active areas of investigation. In this study, we use a recently developed TCF/Lef-LacZ transgenic reporter mouse to characterize the expression of canonical Wnt signaling activity during craniofacial development. We present an atlas of representative sections to show embryonic craniofacial development. Our results demonstrate a pattern of sustained Wnt signaling reporter activity in most tissues which suggests sequential roles in craniofacial development.

No abstract

No abstract