Limb Bud Mesenchyme Cells (LB)

Limb bud mesenchyme cells give rise to most of the future limb elements - bones, cartilage and tendon. Limb bud morphogenesis involves patterning along the proximodistal (PD), anteroposterior (AP) and dorsoventral (DV) axes. The primary direction of limb bud outgrowth defines the PD axis and the formation of the stylopod, zeugopod and autopod. The AP axis is defined by the sequence of digit formation - from thumb to little finger. The DV axis runs from the back of the hand to the palm. In addition to the axes formation, definition of forelimb and hindlimb patterning is a crucial event in limb development. Interactions of multiple signaling cascades leading to expression of limb bud-specific genes enable proper formation of all the axes and define final limb identity and morphology. Limb bud mesenchyme cells represent cell population that express a unique profile of genes throughout various time points of limb bud development.