Expression of Pannexin1 in the outer plexiform layer of the mouse retina and physiological impact of its knockout
Expression of Pannexin1 in the outer plexiform layer of the mouse retina and physiological impact of its knockout
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DOI：
10.1002/cne.23223
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发表时间：
2013-04-01
影响因子：
2.5
通讯作者：
Janssen-Bienhold, Ulrike
中科院分区：
文献类型：
--
作者：
Kranz, Katharina;Dorgau, Birthe;Janssen-Bienhold, Ulrike
Pannexin1 （Panx1）属于一类脊椎动物蛋白，其序列与无脊椎动物间隙连接蛋白innexins具有同源性，并且与脊椎动物间隙连接蛋白（connecins）具有拓扑相似性。与间隙连接通道不同，Panx1形成的是单膜通道，其在神经元回路中的功能作用尚不明确。因此，我们通过反转录聚合酶链反应（RT-PCR）、免疫组织化学和电子显微镜研究了Panx1在野生型和Panx1缺失小鼠视网膜中的亚细胞分布。使用Panx1缺陷小鼠作为模型，通过视网膜电图记录来评估Panx1的生理作用，并确保抗Panx1抗体标记的特异性。Panx1在3a型OFF双极细胞和水平细胞的树突和轴突中表达。Panx1也存在于代表锥体和杆状末端三联突触的横向元素的水平细胞树突中。Panx1基因敲除小鼠的体内视网膜电图显示，与Panx1野生型小鼠相比，在暗沉条件下，Panx1基因敲除小鼠的a波和b波增加。内视网膜的体外视网膜电图证实了对b波的影响。这些结果表明，Panx1通道作为细胞外电流的水槽，使它们可能成为水平细胞向光感受器反馈的中介。中国生物医学工程学报，2013,32(1):391 - 391。(c) 2012 Wiley期刊有限公司
Pannexin1 (Panx1) belongs to a class of vertebrate proteins that exhibits sequence homology to innexins, the invertebrate gap junction proteins, and which also shares topological similarities with vertebrate gap junction proteins, the connexins. Unlike gap junctional channels, Panx1 forms single-membrane channels, whose functional role in neuronal circuits is still unsettled. We therefore investigated the subcellular distribution of Panx1 in the mouse retina of wildtype and Panx1-null mice by reverse-transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and electron microscopy. Use of Panx1-deficient mice served as a model to assess the physiological role of Panx1 by electroretinographic recordings and also to ensure the specificity of the anti-Panx1 antibody labeling. Expression of Panx1 was found in type 3a OFF bipolar cells and in dendrites and axonal processes of horizontal cells. Panx1 was also found in horizontal cell dendrites representing the lateral elements of the triad synapse at cone and rod terminals. In vivo electroretinography of Panx1 knockout mice indicated an increased a- and b-wave compared to Panx1 wildtype mice under scotopic conditions. The effect on the b-wave was confirmed by in vitro electroretinograms from the inner retina. These results suggest that Panx1 channels serve as sinks for extracellular current flow making them possible candidates for the mediation of feedback from horizontal cells to photoreceptors. J. Comp. Neurol. 521:11191135, 2013. (c) 2012 Wiley Periodicals, Inc.