Opposing gradients of ephrin-As and EphA7 in the superior colliculus are essential for topographic mapping in the mammalian visual system
Opposing gradients of ephrin-As and EphA7 in the superior colliculus are essential for topographic mapping in the mammalian visual system
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DOI：
10.1016/j.neuron.2005.05.030
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发表时间：
2005-07-07
期刊：
影响因子：
16.2
通讯作者：
Drescher, U
中科院分区：
文献类型：
--
作者：
Rashid, T;Upton, AL;Drescher, U
在小鼠视网膜丘投射的发育过程中，视网膜轴突最初越过其在上级丘（SC）中的未来终止区（TZs）。TZs的形成是由拓扑学上适当位置的间隙分支引发的。肝配蛋白-As在SC中以降低的后到前梯度表达，并且它们抑制未来TZs后的分支。在这里，我们研究了EphA 7梯度在SC中的作用，其具有与肝配蛋白-A梯度相反的方向。我们发现，在EphA 7突变小鼠的视网膜丘地图被破坏，鼻和颞轴突形成额外的或延长的TZs，分别。在体外，视网膜轴突被排斥在含有EphA 7的条纹上生长。我们的数据支持EphA 7参与抑制未来TZs之前的分支的想法。这些研究结果表明，相反的ephrin-A和EphA梯度所需的适当发展的retinocollicular投影。
During development of the retinocollicular projection in mouse, retinal axons initially overshoot their future termination zones (TZs) in the superior colliculus (SC). The formation of TZs is initiated by interstitial branching at topographically appropriate positions. Ephrin-As are expressed in a decreasing posterior-to-anterior gradient in the SC, and they suppress branching posterior to future TZs. Here we investigate the role of an EphA7 gradient in the SC, which has the reverse orientation to the ephrin-A gradient. We find that in EphA7 mutant mice the retinocollicular map is disrupted, with nasal and temporal axons forming additional or extended TZs, respectively. In vitro, retinal axons are repelled from growing on EphA7-containing stripes. Our data support the idea that EphA7 is involved in suppressing branching anterior to future TZs. These findings suggest that opposing ephrin-A and EphA gradients are required for the proper development of the retinocollicular projection.