Distinct functions of neuronal synaptobrevin in developing and mature fly photoreceptors
Distinct functions of neuronal synaptobrevin in developing and mature fly photoreceptors
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DOI：
10.1002/neu.20284
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发表时间：
2006-10-01
期刊：
影响因子：
--
通讯作者：
Heisenberg, Martin
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文献类型：
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作者：
Rister, Jens;Heisenberg, Martin
神经元突触短缩蛋白（n-Syb，别名VAMP2）是一种突触囊泡膜蛋白，在神经传递中起核心作用，被破伤风神经毒素轻链（TNT）特异性切割，已知TNT可可靠地阻断神经胞吐作用。在这里，我们研究了苍蝇的光感受器向层中的一级中间神经元传递连续的、渐变的信号，并报告了使用UAS/GAL4驱动/效应系统在这些细胞中靶向表达TNT的结果。在光感受器发育过程中表达毒素会导致发育、电生理和行为缺陷。这些可以通过将毒素表达限制在较短的发育时期来区分。应用控制时间和空间表达的方法，我们发现在早期蛹中，TNT损害了视网膜的发育；在蛹中期，在突触形成过程中，TNT引起了严重的椎板发育不良，这种发育不良一直持续到成年，并使椎板上的光感受器-神经元间突触失去功能。最后，在成年期，TNT既不会阻断光感受器中的突触传递，也不会耗尽n-Syb细胞。我们的研究表明，n-Syb在突触发生中具有一种新的细胞类型特异性功能，它可以区分两种突触类型：TNT抗性突触和TNT敏感突触。如果将TNT用于神经回路分析，则需要考虑这些结果。(c) 2006 Wiley期刊公司
Neuronal synaptobrevin (n-Syb, alias VAMP2), a synaptic vesicle membrane protein with a central role in neurotransmission, is specifically cleaved by the light chain of tetanus neurotoxin (TNT) that is known to reliably block neuroexocytosis. Here, we study fly photoreceptors transmitting continuous, graded signals to first order interneurons in the lamina, and report consequences of targeted expression of TNT in these cells using the UAS/GAL4 driver/effector system. Expressing the toxin throughout photoreceptor development causes developmental, electrophysiological, and behavioral defects. These can be differentiated by confining toxin expression to shorter developmental periods. Applying a method for controlled temporal and spatial TNT expression, we found that in the early pupa it impaired the development of the retina; in the mid-pupa, during synapse formation TNT caused a severe hypoplasia of the lamina that persisted into adulthood and left the photoreceptor-interneuron synapses of the lamina without function. Finally, during adulthood TNT neither blocks synaptic transmission in photoreceptors nor depletes the cells of n-Syb. Our study suggests a novel, cell type-specific function of n-Syb in synaptogenesis and it distinguishes between two synapse types: TNT resistant and TNT sensitive ones. These results need to be taken into account if TNT is used for neural circuit analysis. (c) 2006 Wiley Periodicals, Inc.