Regulation of chondrogenesis in early murine limb mesenchyme by BMP signals

Numerous studies have established a critical role for BMP signaling in skeletal development. In the developing axial skeleton, sequential SHH and BMP signals are required for specification of a chondrogenic fate in somitic tissue. A similar paradigm is thought to operate in the limb, but the signals involved are unclear. To investigate the nature of these signals we examined BMP action in mesenchymal populations derived from the early murine limb bud (~ E10.5). These populations exhibited a graded response to BMPs, in which early limb mesenchymal (EL) cells (from the distal hind limb) displayed an anti-chondrogenic response, whereas BMPs promoted chondrogenesis in older cell populations. To better understand the molecular basis of disparate BMP action in these various populations, gene expression profiling with Affymetrix microarrays was employed to identify BMP-regulated genes. These analyses showed that BMPs induced a distinct gene expression pattern in the EL cultures versus later mesenchymal limb populations (IM and LT).

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Karamboulas K, Dranse HJ, Underhill TM