Carbonic anhydrase XIV identified as the membrane CA in mouse retina: strong expression in Muller cells and the RPE
Carbonic anhydrase XIV identified as the membrane CA in mouse retina: strong expression in Muller cells and the RPE
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DOI：
10.1016/j.exer.2005.03.010
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发表时间：
2005-10-01
影响因子：
3.4
通讯作者：
Linser, PJ
中科院分区：
文献类型：
--
作者：
Ochrietor, JD;Clamp, MF;Linser, PJ
神经视网膜中存在碳酸酐酶(CA)活性已有几十年的历史。CA-II是一种可溶性的胞浆亚型，由Muller细胞和无长突细胞亚群表达，被认为是神经视网膜中CA活性的唯一来源。然而，CA-II缺陷小鼠在神经视网膜中保留了CA活性，这意味着该组织中肯定存在另一种异构体。最近，一个完整的膜蛋白CA-XIV被克隆并进行了鉴定。因此，我们试图确定CA-XIV是否在神经视网膜中表达，从而与在CA-II缺失动物中观察到的CA活性有关。对CA-II缺失、CA-XIV缺失和对照小鼠的组织切片进行免疫组织化学分析，以定位CA-XIV亚型以及其他已知的视网膜标志物。免疫印迹和实时RT-PCR分析还检测了CA-XIV在视网膜和其他小鼠组织中的表达。我们在此确定了CA-XIV，一个类似于45 kDa的膜蛋白，在视网膜和肾脏中都有表达。在视网膜中，CA-XIV表达于Muller细胞的质膜上。CA-XIV也存在于视网膜色素上皮的顶膜和基底膜上。本文提供的数据表明，与CA-II一样，CA-XIV在神经视网膜中高度表达，更具体地说，是在Muller细胞中表达。Muller细胞中的两种异构体--一种在细胞质上，另一种在质膜上--的细胞区划表明，这两种酶具有特定和独特的功能。未来的研究将有必要确定CA-II和CA-XIV在小鼠神经视网膜中的功能。(C)2005爱思唯尔有限公司。保留所有权利。
The presence of carbonic anhydrase (CA) activity in the neural retina has been known for several decades. CA-II, a soluble cytoplasmic isoform expressed by Muller cells and a subset of amacrine cells, was thought to be the sole source of CA activity in the neural retina. However, CA-II deficient mice retain CA activity in the neural retina, which implies that another isoform must be present in that tissue. Recently CA-XIV, an integral membrane protein, was cloned and characterized. We, therefore, sought to determine whether CA-XIV is expressed in the neural retina, and hence is responsible for the CA activity observed in CA-II null animals. Immunohistochemical analyses of histological sections from CA-II null, CA-XIV null, and control mice were performed to localize the CA-XIV isoform, as well as other known retinal markers. Immunoblotting and real-time RT-PCR analyses were also performed to test for CA-XIV expression in retina and other mouse tissues. We determined herein that CA-XIV, a similar to 45 kDa membrane protein, is expressed in retina, as it is in kidney. In the retina, CA-XIV is expressed on the plasma membrane of Muller cells. CA-XIV is also found on both the apical and basal membranes of the retinal pigmented epithelium. The data presented here indicate that like CA-II, CA-XIV is highly expressed in the neural retina and, like CA-II, more specifically by the Muller cells. The cellular compartmentalization of the two isoforms in the Muller cell-one cytoplasmic and the other on the plasma membrane-suggest that the two enzymes have specific and unique functions. Future studies will be necessary to assign functions to CA-II and CA-XIV in the mouse neural retina. (c) 2005 Elsevier Ltd. All rights reserved.