Temporal regulation of neuropilin-1 expression and sensitivity to semaphorin 3A in NGF- and NT3-responsive chick sensory neurons.
Temporal regulation of neuropilin-1 expression and sensitivity to semaphorin 3A in NGF- and NT3-responsive chick sensory neurons.
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DOI：
10.1002/neu.10041
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发表时间：
2002-04
期刊：
影响因子：
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通讯作者：
A. Pond;F. K. Roche;Paul C. Letourneau
中科院分区：
文献类型：
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作者：
A. Pond;F. K. Roche;Paul C. Letourneau
细胞外分子semaphorin 3A（Sema 3A）被认为是一种负性的引导因子，参与鸡脊髓背根节感觉轴突的形成。在发育过程中，Sema 3A首先在整个脊髓灰质中表达，但Sema 3A表达后来从背角消失，小口径皮肤传入纤维终止于背角。Sema 3A的表达仍然在腹角，大肌肉本体感受传入终止。有人提出，不同类别的感觉传入Sema 3A的敏感性的时间变化有助于这些感觉传入的不同寻路。本研究比较了从E6-E10鸡胚延伸的NGF（皮肤）和NT 3（本体感受）依赖性感觉轴突的信号蛋白3A受体亚基、神经毡蛋白-1的表达以及生长锥对信号蛋白3A的塌陷反应。生长锥延伸从E6 DRG在NT 3的培养基中表达神经纤毛蛋白-1和崩溃的Sema 3A。从E7到E10，NT 3反应性生长锥表达的神经纤毛蛋白-1水平逐渐降低，对Sema 3A的敏感性降低。另一方面，生长锥延伸从DRG在含神经生长因子的培养基中表达了逐步更高水平的神经纤毛蛋白-1和更高水平的崩溃响应Sema 3A在E6-E10期间。因此，小鸡脊髓中感觉末梢的发育模式可能是由发育中脊髓中Sema 3A表达的变化和伴随的Sema 3A受体亚基神经纤毛蛋白-1的神经元表达的变化引起的。
The extracellular molecule semaphorin 3A (Sema3A) is proposed to be a negative guidance cue that participates in patterning DRG sensory axons in the developing chick spinal cord. During development Sema3A is first expressed throughout the spinal cord gray matter, but Sema3A expression later disappears from the dorsal horn, where small-caliber cutaneous afferents terminate. Sema3A expression remains in the ventral horn, where large-muscle proprioceptive afferents terminate. It has been proposed that temporal changes in the sensitivity of different classes of sensory afferents to Sema3A contribute to the different pathfinding of these sensory afferents. This study compared the expression of the semaphorin 3A receptor subunit, neuropilin-1, and the collapse response of growth cones to semaphorin 3A for NGF (cutaneous)- and NT3 (proprioceptive)-dependent sensory axons extended from E6-E10 chick embryos. Growth cones extended from E6 DRGs in NT3-containing medium expressed neuropilin-1 and collapsed in response to Sema3A. From E7 until E10 NT3-responsive growth cones expressed progressively lower levels of neuropilin-1, and were less sensitive to Sema3A. On the other hand, growth cones extended from DRGs in NGF-containing medium expressed progressively higher levels of neuropilin-1 and higher levels of collapse response to Sema3A over the period from E6-E10. Thus, developmental patterning of sensory terminals in the chick spinal cord may arise from changes in both Sema3A expression in the developing spinal cord and accompanying changes in neuronal expression of the Sema3A receptor subunit, neuropilin-1.