Cloning and functional characterization of novel variants and tissue-specific expression of alternative amino and carboxyl termini of products of slc4a10.
Cloning and functional characterization of novel variants and tissue-specific expression of alternative amino and carboxyl termini of products of slc4a10.
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Slc4a10 产物新变体的克隆和功能表征以及替代氨基和羧基末端的组织特异性表达
DOI：
10.1371/journal.pone.0055974
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Chen LM
中科院分区：
文献类型：
--
作者：
Liu Y;Wang DK;Jiang DZ;Qin X;Xie ZD;Wang QK;Liu M;Chen LM
先前的研究表明，电中性的Na⁺/HCO₃⁻协同转运蛋白NBCn2（SLC4A10）主要在中枢神经系统（CNS）中表达。NBCn2的生理和病理意义已得到充分认识。然而，对于不同NBCn2变体表达的组织特异性知之甚少。此外，对于中枢神经系统以外的系统中NBCn2蛋白的表达也了解不多。在此，我们鉴定出一组新的Slc4a10变体，它们与最初描述的变体不同，其包含一个独特的5′非翻译区，编码一个新的氨基末端（Nt）。电生理学测量表明，具有替代Nt的两种NBCn2变体在非洲爪蟾卵母细胞中都具有典型的电中性Na⁺偶联的HCO₃⁻转运活性。荧光素酶报告基因分析表明，Slc4a10包含两个可替代的启动子，负责表达具有不同极端Nt的两种类型的NBCn2。蛋白质印迹显示，具有原始Nt的NBCn2蛋白主要在中枢神经系统中表达，而具有新Nt的蛋白主要在肾脏中表达，在小肠中也有少量表达。由于可变剪接，已知的NBCn2变体包含两种类型的羧基末端（CT），其区别在于是否可选地包含一个PDZ结合基序。cDNA克隆表明，在上皮组织中表达的几乎所有NBCn2变体都包含该基序，但来自神经组织的绝大多数变体缺乏PDZ结合基序。我们得出结论，Slc4a10产物的可变转录和剪接是以组织特异性的方式进行调控的。我们的发现提供了关键的见解，将极大地影响对NBCn2生理学的研究。
Previous studies have shown that the electroneutral Na+/HCO3 − cotransporter NBCn2 (SLC4A10) is predominantly expressed in the central nervous system (CNS). The physiological and pathological significances of NBCn2 have been well recognized. However, little is known about the tissue specificity of expression of different NBCn2 variants. Moreover, little is known about the expression of NBCn2 proteins in systems other than CNS. Here, we identified a set of novel Slc4a10 variants differing from the originally described ones by containing a distinct 5′ untranslated region encoding a new extreme amino-terminus (Nt). Electrophysiology measurements showed that both NBCn2 variants with alternative Nt contain typical electroneutral Na+-coupled HCO3 − transport activity in Xenopus oocytes. Luciferase reporter assay showed that Slc4a10 contains two alternative promoters responsible for expression of the two types of NBCn2 with distinct extreme Nt. Western blotting showed that NBCn2 proteins with the original Nt are primarily expressed in CNS, whereas those with the novel Nt are predominantly expressed in the kidney and to a lesser extent in the small intestine. Due to alternative splicing, the known NBCn2 variants contain two types of carboxyl-termini (CT) differing in the optional inclusion of a PDZ-binding motif. cDNA cloning showed that virtually all NBCn2 variants expressed in epithelial tissues contain, but the vast majority of those from the neural tissues lack the PDZ-binding motif. We conclude that alternative transcription and splicing of Slc4a10 products are regulated in a tissue-specific manner. Our findings provide critical insights that will greatly influence the study of the physiology of NBCn2.
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影响因子：
3.5
作者：
Groeger, Nicole;Vitzthum, Helga;Boettger, Thomas
通讯作者：
Boettger, Thomas
影响因子：
5.5
作者：
Lee, Seong-Ki;Boron, Walter F.;Parker, Mark D.
通讯作者：
Parker, Mark D.
影响因子：
3.7
作者：
Hilgen G;Huebner AK;Tanimoto N;Sothilingam V;Seide C;Garcia Garrido M;Schmidt KF;Seeliger MW;Löwel S;Weiler R;Hübner CA;Dedek K
通讯作者：
Dedek K
影响因子：
2.9
作者：
Chen LM;Haddad GG;Boron WF
通讯作者：
Boron WF
DOI：
10.1152/ajpregu.00497.2007
发表时间：
2007-12-01
影响因子：
2.8
作者：
Chen, Li-Ming;Choi, Inyeong;Boron, Walter F.
通讯作者：
Boron, Walter F.