BMPs induce dermal markers and ectopic feather tracts

Abstract

Bone morphogenetic protein (BMP) signaling is known to be involved in multiple inductive events during embryogenesis including the development of amniote skin. Here, we demonstrate that early application of BMP-2 to the lateral trunk of chick embryos induces the formation of dense dermis, which is competent to participate in feather development. We show that BMPs induce the dermis markers Msx-1 and cDermo-1 and lead to dermal proliferation, to expression of beta-catenin, and eventually to the formation of ectopic feather tracts in originally featherless regions of chick skin. Moreover, we present a detailed analysis of cDermo-1 expression during early feather development. The data implicate that cDermo-1 is located downstream of BMP in a signaling pathway that leads to condensation of dermal cells. The roles of BMP and cDermo-1 during development of dermis and feather primordia are discussed.

Hedgehog-responsive mesenchymal clusters direct patterning and emergence of intestinal villi

“…Quantitation of these complex elements of tissue pattern is essential to establish a ruler against which to accurately compare perturbances in the system. The intestinal mesenchymal clusters have several similarities to the mesenchymal condensates involved in the patterning of hair, teeth, tongue papillae, feathers, and hair follicles (13,26,(33)(34)(35)(36)(37)(38)(39). Like the dermal condensates associated with feather formation in the chick, villus clusters first arise in anterior and dorsal midline regions and then spread posteriorly and laterally (33).…”

Drm/Gremlin, a BMP antagonist, defines the interbud region during feather development.

“…This observation suggests that drm/gremlin is one of the earliest genes expressed in the dermis along with the bHLH transcription factor Dermo-1 (Scaal et al, 2002). However, after feather placode formation Dermo-1 is principally expressed in the dermal condensations, whereas the expression of drm is restricted to the interbud dermis.…”

“…The BMPs overexpression elicits different effects according to the skin developmental stage: at early stages (17-23 HH) implantation of beads soaked with BMPs can induce ectopic feather formation in a particular limited region of the lateral trunk (Scaal et al, 2002) while all over and at later stage (29 HH) BMPs inhibit feather formation (Jung et al, 1998;Noramly and Morgan, 1998). …”

The molecular basis of amphibian limb regeneration: integrating the old with the new

“…Given that Msx-1 is known to be causally linked to fragmentation, 41 this may indicate that there are factors in blastemas that regulate Msx expression. Several signaling molecules are known to have this ability, including members of the FGF, Wnt, and BMP signaling pathways, 32,[49][50][51][52][53][54] which are obvious candidates for further studies.…”