The early limb bud consists of mesenchymal limb progenitors derived from the lateral plate mesoderm (LPM). The LPM also gives rise to the mesodermal components of the flank and neck. However, the cells at these other levels cannot produce the variety of cell types found in the limb. Taking advantage of a direct reprogramming approach, we find a set of factors (Prdm16, Zbtb16, and Lin28a) normally expressed in the early limb bud and capable of imparting limb progenitor-like properties to mouse non-limb fibroblasts. The reprogrammed cells show similar gene expression profiles and can differentiate into similar cell types as endogenous limb progenitors. The further addition of Lin41 potentiates the proliferation of the reprogrammed cells. These results suggest that these same four factors may play pivotal roles in the specification of endogenous limb progenitors.

早期肢芽由源自侧板中胚层（LPM）的间充质肢体祖细胞组成。LPM 还产生侧腹和颈部的中胚层成分。然而，这些其他水平的细胞无法产生肢体中发现的多种细胞类型。利用直接重编程方法，我们发现了一组通常在早期肢芽中表达的因子（Prdm16、Zbtb16 和 Lin28a），并且能够将肢体祖细胞样特性赋予小鼠非肢体成纤维细胞。重编程的细胞显示出相似的基因表达谱，并且可以分化成与内源性肢体祖细胞相似的细胞类型。进一步添加 Lin41 可增强重编程细胞的增殖。这些结果表明，这四个因素可能在内源性肢体祖细胞的规范中发挥关键作用。