Tissue specificity and alternative splicing of the Na+/Ca2+ exchanger isoforms NCX1, NCX2, and NCX3 in rat
Tissue specificity and alternative splicing of the Na+/Ca2+ exchanger isoforms NCX1, NCX2, and NCX3 in rat
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DOI：
10.1152/ajpcell.1997.272.4.c1250
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发表时间：
1997-04-01
影响因子：
5.5
通讯作者：
Philipson, KD
中科院分区：
文献类型：
--
作者：
Quednau, BD;Nicoll, DA;Philipson, KD
编码Na+/Ca 2+交换剂NCX 1的基因的特征在于六个外显子（A、B、C、D、E和F）的簇，其编码蛋白质的大胞内环的COOH末端中的可变区。这些外显子的选择性剪接产生NCX 1的多种组织特异性变体。使用逆转录-聚合酶链反应，我们分析了8个先前描述的和4个新的剪接异构体的NCX 1在各种各样的组织和细胞。外显子A和B是相互排斥的，如在早期的研究中所示，并且含有外显子A的剪接异构体优先在心脏、脑和骨骼肌中表达，而含有外显子B的剪接变体在除心脏之外的所有大鼠组织中发现。Na+/Ca 2+交换器的第二和第三同种型，NCX 2和NCX 3，在对应于NCX 1可变区部分的胞内环中显示37个氨基酸的缺失。我们通过逆转录-聚合酶链反应鉴定了脑和骨骼肌中NCX 3的三种剪接异构体。这些剪接变体通过包括与NCX 1外显子A或B等同的两个选择性外显子中的任一个以及通过包括或排除与NCX 1外显子C等同的序列而产生。我们没有检测到NCX 2的任何选择性剪接。我们检查了新生大鼠和成年大鼠的选定组织，发现骨骼肌中NCX 1和NCX 3剪接异构体的发育调节。在培养的皮层神经元、星形胶质细胞和少突胶质细胞中也检测到NCX 1和NCX 3的特异性亚型模式。我们提出了一个新的术语来区分不同的剪接变异体的个人NCX亚型。
The gene coding for the Na+/Ca2+ exchanger NCX1 is characterized by a cluster of six exons (A, B, C, D, E, and F) coding for a variable region in the COOH terminus of the large intracellular loop of the protein. Alternative splicing of these exons generates multiple tissue-specific variants of NCX1. Using reverse transcriptase-polymerase chain reaction, we analyzed eight previously described and four new splicing isoforms of NCX1 in a wide variety of tissues and cells. Exons A and B are mutually exclusive, as shown in earlier studies, and splicing isoforms containing exon A are preferentially expressed in heart, brain, and skeletal muscle, whereas splicing variants with exon B are found in all rat tissues except heart. The second and third isoforms of the Na+/Ca2+ exchanger, NCX2 and NCX3, show a deletion of 37 amino acids in the intracellular loop corresponding to parts of the variable region of NCX1. We identified three splicing isoforms of NCX3 in brain and skeletal muscle by reverse transcriptase-polymerase chain reaction. These splice variants are generated by including either of two alternative exons equivalent to the NCX1 exon A or B and by including or excluding a sequence equivalent to the NCX1 exon C. We did not detect any alternative splicing of NCX2. We examined selected tissues from neonatal and adult rats and found developmental regulation for NCX1 and NCX3 splicing isoforms in skeletal muscle. Specific isoform patterns were also detected for NCX1 and NCX3 in cultured cortical neurons, astrocytes, and oligodendrocytes. We suggest a new terminology to distinguish the different splice variants of individual NCX isoforms.