Assessing the role of cell-surface molecules in central synaptogenesis in the Drosophila visual system.
Assessing the role of cell-surface molecules in central synaptogenesis in the Drosophila visual system.
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DOI：
10.1371/journal.pone.0083732
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Suzuki T
中科院分区：
文献类型：
--
作者：
Berger-Müller S;Sugie A;Takahashi F;Tavosanis G;Hakeda-Suzuki S;Suzuki T
中枢神经系统的一个标志是它在突触层的空间和功能组织。在神经元发育过程中，轴突与潜在的突触后元件形成短暂的接触，并在特定的层与适当的伙伴建立突触。这些过程受突触细胞黏附分子的调节。在果蝇的视觉系统中，R7和R8光感受器亚型靶向不同的层，并在轴突的刻板位置形成通过的突触前终末。一种富含亮氨酸重复序列的跨膜蛋白Caps选择性地在R8轴突及其受体层中表达，这导致了一种引人注目的假说，即Caps通过亲性黏附介导了R8突触的特异性。与这一假设相矛盾的是，我们的结果表明，Caps在果蝇光感受器的突触层靶向和突触形成中没有显著作用，并且R8靶层的特异性识别不涉及Caps的同嗜性轴突-靶相互作用。我们产生了表达标记突触标记的果蝇，以评估R7和R8光感受器中突触的存在和定位。这些遗传工具被用来评估当轴突被迫通过表达轴突引导分子来靶向异常层时，突触轮廓是如何受到影响的。当R7轴突被错误定位到R8受体层时，R7要么保持类似R7的突触轮廓，要么根据过度表达的蛋白获得与R8相似的轮廓。当R7轴突被重定向到更浅的延髓层时，突触前终末的数量减少。这些结果表明，细胞表面分子能够以部分细胞自主的方式通过改变轴突终末身份来决定突触位置，但特定位置的突触前形成也需要突触前和突触后元件之间的复杂相互作用。
A hallmark of the central nervous system is its spatial and functional organization in synaptic layers. During neuronal development, axons form transient contacts with potential post-synaptic elements and establish synapses with appropriate partners at specific layers. These processes are regulated by synaptic cell-adhesion molecules. In the Drosophila visual system, R7 and R8 photoreceptor subtypes target distinct layers and form en passant pre-synaptic terminals at stereotypic loci of the axonal shaft. A leucine-rich repeat transmembrane protein, Capricious (Caps), is known to be selectively expressed in R8 axons and their recipient layer, which led to the attractive hypothesis that Caps mediates R8 synaptic specificity by homophilic adhesion. Contradicting this assumption, our results indicate that Caps does not have a prominent role in synaptic-layer targeting and synapse formation in Drosophila photoreceptors, and that the specific recognition of the R8 target layer does not involve Caps homophilic axon-target interactions. We generated flies that express a tagged synaptic marker to evaluate the presence and localization of synapses in R7 and R8 photoreceptors. These genetic tools were used to assess how the synaptic profile is affected when axons are forced to target abnormal layers by expressing axon guidance molecules. When R7 axons were mistargeted to the R8-recipient layer, R7s either maintained an R7-like synaptic profile or acquired a similar profile to r8s depending on the overexpressed protein. When R7 axons were redirected to a more superficial medulla layer, the number of presynaptic terminals was reduced. These results indicate that cell-surface molecules are able to dictate synapse loci by changing the axon terminal identity in a partially cell-autonomous manner, but that presynapse formation at specific sites also requires complex interactions between pre- and post-synaptic elements.
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影响因子：
64.8
作者：
Morey, Marta;Yee, Susan K.;Herman, Tory;Nern, Aljoscha;Blanco, Enrique;Zipursky, S. Lawrence
通讯作者：
Zipursky, S. Lawrence
影响因子：
5.7
作者：
Lu, Bai;Wang, Kuan Hong;Nose, Akinao
通讯作者：
Nose, Akinao
影响因子：
4.6
作者：
Kohsaka, Hiroshi;Nose, Akinao
通讯作者：
Nose, Akinao
DOI：
10.1007/978-3-7091-0932-8_5
发表时间：
2012-01-01
期刊：
SYNAPTIC PLASTICITY: DYNAMICS, DEVELOPMENT AND DISEASE
影响因子：
--
作者：
Bukalo, Olena;Dityatev, Alexander
通讯作者：
Dityatev, Alexander
影响因子：
2.7
作者：
Sakurai, Kayoko T.;Kojima, Tetsuya;Hayashi, Shigeo
通讯作者：
Hayashi, Shigeo