Synaptotagmin I and II are present in distinct subsets of central synapses
Synaptotagmin I and II are present in distinct subsets of central synapses
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DOI：
10.1002/cne.21381
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发表时间：
2007-07-10
影响因子：
2.5
通讯作者：
Sanes, Joshua R.
中科院分区：
文献类型：
--
作者：
Fox, Michael A.;Sanes, Joshua R.
突触素1和2(syt1，syt2)是突触小泡相关的膜蛋白，是突触前神经末梢快速释放神经递质的钙感受器。在这里，我们展示了广泛使用的单抗，单抗48和ZNP-1，在多种物种中染色神经末梢，并在小鼠中分别识别syt 1和syt 2。利用这些抗体，我们检测了这些突触素亚型在小鼠中枢神经系统中的突触定位。Syt1和Syt2主要定位于视网膜、海马体、小脑和斜方体正中核(MNTB)的不同突触亚群。在MNTB，syt1和syt2存在于同一突触后主神经元的不同突触前终末。在视网膜中，水平和非双极细胞终末含有Syt2，而大多数其他终末含有Syt1。Syt1在未成熟视网膜中的定位与成人相似；然而，Syt2的定位在围产期表现出显著的不同，并在睁开眼睛之前继续发生显著变化。例如，在成人视网膜中缺乏syt 2的星状突起无长突细胞，在出生后的头两周瞬时表达syt 2。除了在空间和时间分布上的差异外，在视网膜和小脑中还观察到不同物种的突触素定位的差异。突触素亚型在细胞、时间和物种上的特异性表达表明，每种亚型在神经递质释放中可能具有不同的功能。
Synaptotagmin 1 and 2 (syt 1, syt 2) are synaptic vesicle-associated membrane proteins that act as calcium sensors for fast neurotransmitter release from presynaptic nerve terminals. Here we show that widely used monoclonal antibodies, mab 48 and znp-1, stain nerve terminals in multiple species and, in mouse, recognize syt 1 and syt 2, respectively. With these antibodies, we examined the synaptic localization of these synaptotagmin isoforms in the mouse central nervous system. Syt 1 and syt 2 are localized predominantly to different subsets of synapses in retina, hippocampus, cerebellum, and median nucleus of the trapezoid body (MNTB). In the MNTB, syt 1 and syt 2 are present in different presynaptic terminals on the same postsynaptic principal neuron. In retina, horizontal and OFF-bipolar cell terminals contain syt 2, whereas most other terminals contain syt 1. Syt 1 localization in the immature retina resembles that seen in adult; however, syt 2 localization appears strikingly different at perinatal ages and continues to change dramatically prior to eye opening. For example, starburst amacrine cells, which lack syt 2 in adult retina, transiently express syt 2 during the first 2 postnatal weeks. In addition to differences in spatial and temporal distribution, species-specific differences in synaptotagmin localization were observed in retina and cerebellum. The cell-, temporal-, and species-specific expression of synaptotagmin isoforms suggests that each may have distinct functions in neurotransmitter release.