A role for gradient en expression in positional specification on the optic tectum
A role for gradient en expression in positional specification on the optic tectum
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DOI：
10.1016/s0896-6273(00)80023-9
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发表时间：
1996-01-01
期刊：
影响因子：
16.2
通讯作者：
Nakamura, H
中科院分区：
文献类型：
--
作者：
Itasaki, N;Nakamura, H
视顶盖是非哺乳类脊椎动物的主要视觉中枢，以地形学上有序的方式接受视网膜纤维。en（en-1和en-2，果蝇节极性基因的同源物）在顶盖原基中以吻尾梯度表达，大约在视网膜顶盖投影图的极性被确定的阶段。在这里，我们报告分散的en表达，逆转录病毒基因转移引起的，扰乱了视网膜顺序。鼻视网膜纤维，通常识别顶盖的尾侧（强en表达侧）作为目标，在异位部位分叉，好像它们找到了它们的目标，或者退化。颞视网膜纤维，通常识别顶盖的喙侧（弱en表达侧）作为目标，也受到影响，在某些情况下，变性或防止神经支配顶盖。这些结果表明，梯度en表达定义的顶盖沿着的吻尾轴的位置标识。
The optic tectum, the primary visual center in nonmammalian vertebrates, receives retinal fibers in a topographically ordered manner. en (en-1 and en-2, homologs of the Drosophila segment polarity gene engrailed) is expressed in the tectal primordium in a rostrocaudal gradient, around the stage when the polarity of the retinotectal projection map is being determined. Here we report that scattered en expression, caused by retroviral gene transfer, perturbed the retinotopic order. Nasal retinal fibers, which normally recognize the caudal side of the tectum (strong en expression side) as a target, arborized at ectopic sites, as if they found their targets, or degenerated. Temporal retinal fibers, which normally recognize the rostral side of the tectum (weak en expression side) as a target, were also affected in some cases by degeneration or prevention of innervation in the tectum. These results suggest that gradient en expression defines the positional identity of the tectum along the rostrocaudal axis.