BACKGROUND The basic ground plan of vertebrate hindbrain is established through a process of segmentation, which generates eight transient lineage-restricted cellular compartments called rhombomeres (r). The segments adopt distinct individual identities in response to axial patterning signals. It is unclear whether signaling between rhombomeres plays a conserved role in regulating segmental patterning during hindbrain development. RESULTS Using tissue manipulations of rhombomeres in chicken embryos, we have uncovered roles for r2 and r4 in regulating the expression of EphA4 in r3 and r5. Perturbations of signaling pathways reveal that these regulatory inputs from r2 and r4 into EphA4 expression are mediated independent of inputs from Krox20 through cues involving fibroblast growth factor (FGF) signaling. These interactions are stage dependent and are set up in embryos with <10 somites. CONCLUSIONS We show that r2 and r4 function as temporally dynamic signaling centers in the early patterning of adjacent hindbrain segments and this activity is dependent upon the FGF pathway. These results reveal that inter-rhombomeric signaling is a conserved feature of the regulatory networks that control the specification of individual rhombomere identities in vertebrate hindbrain segmentation. However, the timing of when restricted domains of FGF signaling are coupled to formation of r4 may vary between the species.

中文翻译：

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菱形之间的相互作用揭示了成纤维细胞生长因子信号传导在EphA4表达的节段调节中的作用。

背景技术脊椎动物后脑的基本平面图是通过分割过程建立的，该分割过程产生了八个短暂的沿谱系限制的细胞区室，称为rhombomeres（r）。这些段响应于轴向图案化信号而采用不同的个体身份。尚不清楚菱形之间的信号传导是否在调节后脑发育过程中的节段模式中发挥保守作用。结果通过组织处理鸡胚中的菱形小节，我们发现了r2和r4在调节r3和r5中EphA4表达中的作用。信号转导通路的扰动表明，从r2和r4到EphA4表达的这些调控输入是通过涉及成纤维细胞生长因子（FGF）信号的提示介导的，与Krox20的输入无关。这些相互作用是阶段依赖性的，并建立在＜10个节段的胚胎中。结论我们显示，r2和r4在相邻后脑节段的早期模式中起时间动态信号中心的作用，并且这种活性取决于FGF途径。这些结果表明，菱形间信号是调控网络的保守特征，该网络控制脊椎动物后脑分割中单个菱形身份的规范。然而，何时FGF信号转导的限制性结构域与r4的形成偶联的时机可能在物种之间变化。这些结果表明，菱形间信号是调控网络的保守特征，该网络控制脊椎动物后脑分割中单个菱形身份的规范。然而，何时FGF信号转导的限制性结构域与r4的形成偶联的时机可能在物种之间变化。这些结果表明，菱形间信号是调控网络的保守特征，该网络控制脊椎动物后脑分割中单个菱形身份的规范。但是，FGF信号的限制性结构域与r4形成偶联的时机可能会因种而异。