The canine betaine gamma-amino-n-butyric acid transporter gene: diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.
The canine betaine gamma-amino-n-butyric acid transporter gene: diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.
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犬甜菜碱γ-氨基-正丁酸转运蛋白基因：多种mRNA亚型受高渗性调节，并以组织特异性方式表达。
DOI：
10.1073/pnas.92.4.1072
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发表时间：
1995
影响因子：
11.1
通讯作者：
Handler,JS
中科院分区：
文献类型：
--
作者：
Takenaka,M;Bagnasco,SM;Preston,AS;Uchida,S;Yamauchi,A;Kwon,HM;Handler,JS
Na（+）-和Cl（-）-偶联的甜菜碱转运蛋白，命名为BGT 1，是神经递质转运蛋白基因家族的成员，负责甜菜碱在高渗Madin-Darby犬肾（MDCK）细胞中的蓄积，并可能在高渗肾髓质中蓄积。犬的甜菜碱γ-氨基-正丁酸转运蛋白基因已被克隆和分析。该基因长度超过28 kb，由18个外显子组成。该基因的5'端具有三个可选择的第一外显子（1A、1B和1C+D）。BGT 1 mRNA的分析显示，在5'非翻译序列中存在相当大的差异，这是由于三个不同的5'末端基序（A、B和C），随后是一个替代基序（D）以及两个用于剪接的内部受体位点。8种BGT 1 mRNA根据5'端序列分为A、B、C 3种类型。使用A、B或C基序特异性探针的北方印迹分析显示，高渗诱导MDCK细胞中的所有三种类型。逆转录和聚合酶链反应表明，每种类型的表达在组织特异性的方式。引物延伸和/或RNA酶保护试验以及转染MDCK细胞的试验表明，外显子1A、1B和1C+D在独立启动子的控制下具有独立的转录起始位点。不同的mRNA亚型受高渗调节，并以组织特异性方式表达。
The Na(+)- and Cl(-)-coupled betaine transporter, designated BGT1, a member of the neurotransmitter transporter gene family, is responsible for accumulation of betaine in hypertonic Madin-Darby canine kidney (MDCK) cells and presumably in the hypertonic renal medulla. The canine gene for the betaine gamma-amino-n-butyric acid transporter has been cloned and analyzed. The gene extends over 28 kb and consists of 18 exons. The 5' end of the gene has three alternative first exons (1A, 1B, and 1C+D). Analysis of BGT1 mRNA revealed that there is considerable divergence in the 5' untranslated sequence resulting from three different 5' end motifs (A, B, and C) followed by an alternative motif (D) as well as two internal acceptor sites for splicing. Eight kinds of BGT1 mRNA were classified into three types (A, B, and C) according to the 5' end sequence. Northern blot analysis using probes specific for the A, B, or C motif revealed that hypertonicity induces all three types in MDCK cells. Reverse transcription and polymerase chain reaction showed that each type was expressed in a tissue-specific manner. Primer extension and/or RNase protection assays as well as transfection assays into MDCK cells demonstrated that exons 1A, 1B, and 1C+D have independent transcription initiation sites under control of independent promoters. Diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.