The Bone Morphogenetic Protein (BMP) family reiteratively signals to direct disparate cellular fates throughout embryogenesis. In the developing dorsal spinal cord, multiple BMPs are required to specify sensory interneurons (INs). Previous studies suggested that the BMPs act as concentration-dependent morphogens to direct IN identity, analogous to the manner in which sonic hedgehog patterns the ventral spinal cord. However, it remains unresolved how multiple BMPs would cooperate to establish a unified morphogen gradient. Our studies support an alternative model: BMPs have signal-specific activities directing particular IN fates. Using chicken and mouse models, we show that the identity, not concentration, of the BMP ligand directs distinct dorsal identities. Individual BMPs promote progenitor patterning or neuronal differentiation by their activation of different type I BMP receptors and distinct modulations of the cell cycle. Together, this study shows that a ‘mix and match’ code of BMP signaling results in distinct classes of sensory INs.

中文翻译：

---

BMPs 使用信号特异性非形态发生活动指导发育中的脊髓中的感觉中间神经元身份

骨形态发生蛋白 (BMP) 家族反复发出信号以指导整个胚胎发生过程中不同的细胞命运。在发育中的脊髓背侧，需要多个 BMP 来指定感觉中间神经元 (IN)。以前的研究表明，BMP 作为浓度依赖性形态发生素来指导 IN 身份，类似于声波刺猬模式腹侧脊髓的方式。然而，多个 BMP 将如何合作以建立统一的形态发生梯度仍然没有解决。我们的研究支持另一种模型：BMP 具有指导特定 IN 命运的信号特异性活动。使用鸡和小鼠模型，我们表明 BMP 配体的身份而不是浓度指导不同的背侧身份。单个 BMP 通过激活不同的 I 型 BMP 受体和不同的细胞周期调节来促进祖细胞模式或神经元分化。总之，这项研究表明 BMP 信号的“混合和匹配”代码会导致不同类别的感觉 IN。