Neural crest cells are multipotent progenitor cells that can generate both ectodermal cell types, such as neurons, and mesodermal cell types, such as smooth muscle. The mechanisms controlling this cell fate choice are not known. The basic Helix-loop-Helix (bHLH) transcription factor Twist1 is expressed throughout the migratory and post-migratory cardiac neural crest. Twist1 ablation or mutation...

The anteroposterior axis of the developing embryo becomes morphologically apparent at the onset of gastrulation with the formation of the primitive streak. This structure, where the first mesodermal cells arise, marks the posterior aspect of the embryo. To examine the potential role of non-mesodermal signals in specifying posterior (hematopoietic and endothelial) cell fates in the mouse embryo,...

In amphibian embryos, formation of the basic body plan depends on positional differences in the mesoderm. Although peptide growth factors involved in mesoderm induction have tentatively been identified, additional signals are required to generate pattern in this tissue. We have isolated a Xenopus cDNA for a Wnt-1 related gene, designated Xwnt-8, which is activated in response to mesoderm-induci...

An odontogenic myxoma of a maxilla has been examined. Histochemistry of the mucosubstance indicated that hyaluronic acid and chondroitin sulphate were present. On ultrastructural examination many of the cells in the myxomatous tissue were seen with prominent rough endoplasmic reticulum, suggesting a secretory function, and possibly the myxomatous ground substance was produced by these cells. Ce...

Grafting, together with tissue identification by monoclonal antibodies, has been used to study the allocation of Xenopus animal cap cells to the ectodermal or mesodermal lineages. Animal cap cells become responsive at stage 61 and lose responsiveness to mesodermal induction at, or just after, stage 10i (depending on the batch of embryos). The ability of the vegetal yolky cells to induce mesoder...

Convergent extension of the mesoderm is the major driving force of vertebrate gastrulation. During this process, mesodermal cells move toward the future dorsal side of the embryo, then radically change behavior as they initiate extension of the body axis. How cells make this transition in behavior is unknown. We have identified the scaffolding protein and tumor suppressor Gravin as a key regula...

A central issue in developmental biology is how the deployment of generic signaling proteins produces diverse specific outcomes. We show that Drosophila FGF is used, only in males, to recruit mesodermal cells expressing its receptor to become part of the genital imaginal disc. Male-specific deployment of FGF signaling is controlled by the sex determination regulatory gene doublesex. The recruit...

The field of tissue engineering entered a new era with the development of human pluripotent stem cells (hPSCs), which are capable of unlimited expansion whilst retaining the potential to differentiate into all mature cell populations. However, these cells harbor significant risks, including tumor formation upon transplantation. One way to mitigate this risk is to develop expandable progenitor c...

Activation of transforming growth factor-beta (TGF-beta) receptors typically elicits mesodermal development, whereas inhibition of this pathway induces neural fates. In vitro differentiated mouse embryonic stem (ES) cells with deletion of the TGF-beta pathway-related factors Smad4 or Cripto exhibited increased numbers of neurons. Cripto-/- ES cells developed into neuroecto-/epidermal cell types...

Stem-cell differentiation to desired lineages requires navigating alternating developmental paths that often lead to unwanted cell types. Hence, comprehensive developmental roadmaps are crucial to channel stem-cell differentiation toward desired fates. To this end, here, we map bifurcating lineage choices leading from pluripotency to 12 human mesodermal lineages, including bone, muscle, and hea...