Ephrin-B2 reverse signaling is required for topography but not pattern formation of lateral superior olivary inputs to the inferior colliculus.
Ephrin-B2 reverse signaling is required for topography but not pattern formation of lateral superior olivary inputs to the inferior colliculus.
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DOI：
10.1002/cne.23243
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发表时间：
2013-05-01
影响因子：
2.5
通讯作者：
Gabriele, Mark L.
中科院分区：
文献类型：
--
作者：
Wallace, Matthew M.;Kavianpour, Sarah M.;Gabriele, Mark L.
已知Eph-肝配蛋白的分级和模块化表达为发育中的神经系统中地形图和图案的形成提供位置信息。以前，我们已经表明，肝配蛋白-B2的表达是在一个连续的梯度在整个tonotopic轴的下丘中央核（CNIC），而模式是不连续的和模块化的外侧皮质的IC（LCIC）。本研究探讨了ephrin-B2信号在听觉发作前从外侧上级橄榄核（LSO）投射到CNIC和LCIC的发展中的参与。在新生儿固定的组织制剂中使用顺行和逆行荧光示踪方法来比较野生型和肝配蛋白-B2 lacZ/+小鼠（严重受损的反向信号传导）中的地形图绘制和LSO层/模块的建立。出生时，先锋LSO轴突占据同侧IC在这两个群体，但延迟对侧ephrin-B2 lacZ/+突变体。由听力发作，野生型和突变体的预测形成可辨别的层双边的CNIC和模块化的安排内同侧LCIC。相比之下，肝配蛋白-B2 lacZ/+小鼠在LSO-IC投射中缺乏可靠的拓扑结构，这表明正常投射映射需要全功能的肝配蛋白-B2反向信号传导。总之，这些肝配蛋白-B2的发现与已知的EphA 4的共表达配对，表明这些信号蛋白在经验之前建立功能性听觉回路中的重要性。
Graded and modular expressions of Eph-ephrins are known to provide positional information for the formation of topographic maps and patterning in the developing nervous system. Previously we have shown that ephrin-B2 is expressed in a continuous gradient across the tonotopic axis of the central nucleus of the inferior colliculus (CNIC), whereas patterns are discontinuous and modular in the lateral cortex of the IC (LCIC). The present study explores the involvement of ephrin-B2 signaling in the development of projections to the CNIC and LCIC arising from the lateral superior olivary nuclei (LSO) prior to hearing onset. Anterograde and retrograde fluorescent tracing methods in neonatal fixed tissue preparations were used to compare topographic mapping and the establishment of LSO layers/modules in wild-type and ephrin-B2lacZ/+ mice (severely compromised reverse signaling). At birth, pioneer LSO axons occupy the ipsilateral IC in both groups but are delayed contralaterally in ephrin-B2lacZ/+ mutants. By the onset of hearing, both wild-type and mutant projections form discernible layers bilaterally in the CNIC and modular arrangements within the ipsilateral LCIC. In contrast, ephrin-B2lacZ/+ mice lack a reliable topography in LSO-IC projections, suggesting that fully functional ephrin-B2 reverse signaling is required for normal projection mapping. Taken together, these ephrin-B2 findings paired with known coexpression of EphA4 suggest the importance of these signaling proteins in establishing functional auditory circuits prior to experience.
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影响因子：
16.2
作者：
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通讯作者：
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