Differential expression of syntaxin-1 and synaptophysin in the developing and adult human retina
Differential expression of syntaxin-1 and synaptophysin in the developing and adult human retina
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DOI：
10.1007/bf02703642
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发表时间：
2001-06-01
影响因子：
2.9
通讯作者：
Wadhwa, S
中科院分区：
文献类型：
--
作者：
Nag, TC;Wadhwa, S
突触素和突触素-1是分别与神经末梢的突触小泡和突触前活动区相关的膜蛋白。前者被认为是突触发生的一个很好的标志；然而，这一方面在Synaxin-1中还不清楚。本研究用免疫组织化学方法检测了这两种蛋白在发育中的人视网膜中的表达，并与它们在出生后至成年视网膜中的分布进行了比较。在内丛状层，两者在妊娠11-12周时同时表达，据报道，当突触发生在中央视网膜时。然而，在外丛状层，免疫反应在16周时明显。它们在两个丛状层中的表达遵循从中心到外围的梯度。在未成熟的光感受器、无长突细胞和神经节细胞中均有表达，但突触素在双极细胞及其轴突中有不同的定位，在一些水平细胞中也有突触素的表达。在出生后至成年的视网膜，突触素免疫反应主要分布在位于外丛状层的光感受器终末，相反，突触素-1位于该层的一条薄带中。而在内丛状层，两者分布均匀。我们的研究表明：(I)Synaxin-1与突触的形成是平行的；(Ii)人类视网膜中的突触发生可能遵循从中心到外围的梯度；(Iii)Synaxin-1可能不存在于外丛状层的带状突触中，但可能出现在光感受器和水平细胞的突触前终末，从这些细胞中的定位可以明显看出，这在任何脊椎动物的视网膜中都是未见报道的。
Synaptophysin and syntaxin-1 are membrane proteins that associate with synaptic vesicles and presynaptic active zones at nerve endings, respectively. The former is known to be a good marker of synaptogenesis; this aspect, however, is not clear with syntaxin-1. In this study, the expression of both proteins was examined in the developing human retina and compared with their distribution in postnatal to adult retinas, by immunohistochemistry. In the inner plexiform layer, both were expressed simultaneously at 11-12 weeks of gestation, when synaptogenesis reportedly begins in the central retina. In the outer plexiform layer, however, the immunoreactivities were prominent by 16 weeks of gestation. Their expression in both plexiform layers followed a centre-to-periphery gradient. The immunoreactivities for both proteins were found in the immature photoreceptor, amacrine and ganglion cells; however, synaptophysin was differentially localized in bipolar cells and their axons, and syntaxin was present in some horizontal cells. In postnatal-to-adult retinas, synaptophysin immunoreactivity was prominent in photoreceptor terminals lying in the outer plexiform layer; on the contrary, syntaxin-1 was present in a thin immunoreactive band in this layer. In the inner plexiform layer, however, both were homogeneously distributed. Our study suggests that (i) syntaxin-1 appears in parallel with synapse formation; (ii) synaptogenesis in the human retina might follow a centre-to-periphery gradient; (iii) syntaxin-1 is likely to be absent from ribbon synapses of the outer plexiform layer, but may occur at presynaptic terminals of photoreceptor and horizontal cells, as is apparent from its localization in these cells, which is hitherto unreported for any vertebrate retina.