Department of Biophysics, Center for Molecular Biomedicine, University of Jena, Jena, Germany.
J Mol Neurosci. 2010 Jun;41(2):310-4. doi: 10.1007/s12031-009-9315-3. Epub 2009 Dec 2.
The voltage-gated sodium channel subtype Na(V)1.8 (SCN10A) is exclusively expressed in dorsal root ganglia (DRG) and plays a critical role in pain perception. We isolated mRNA from human, rat, and mouse DRGs and screened for alternatively spliced isoforms of the SCN10A mRNA using 454 sequencing. In all three species, we found an event of subtle alternative splicing at a NAGNAG tandem acceptor that results in isoforms including or lacking glutamine 1030 (Na(V)1.8+Q and Na(V)1.8-Q, respectively) within the cytoplasmic loop between domains II and III. The relative amount of Na(V)1.8-Q mRNA in adult DRG was measured with 14.1 +/- 0.1% in humans and 11.2 +/- 0.2% in rats. This is in contrast to an abundance of 64.3 +/- 0.3% in mouse DRG. Thus, the NAGNAG tandem acceptor in SCN10A is conserved among rodents and humans but its alternative usage apparently occurs with species-specific abundance. Analysis of human Na(V)1.8+Q and -Q isoforms in whole-cell patch-clamp experiments after heterologous expression in the neuroblastoma cell line Neuro-2A revealed no obvious impact of the splicing event on channel function.
电压门控钠离子通道亚型 Na(V)1.8（SCN10A）仅在背根神经节（DRG）中表达，在痛觉感知中发挥关键作用。我们从人、大鼠和小鼠的 DRG 中分离 mRNA，并用 454 测序筛选 SCN10A mRNA 的可变剪接异构体。在这三种物种中，我们在 NAGNAG 串联受体处发现了一个微妙的可变剪接事件，导致包含或缺乏第 II 和 III 结构域之间的细胞质环中 1030 号谷氨酰胺（Na(V)1.8+Q 和 Na(V)1.8-Q，分别）的异构体。成年 DRG 中 Na(V)1.8-Q mRNA 的相对含量用人 14.1 +/- 0.1%和大鼠 11.2 +/- 0.2%来衡量。相比之下，小鼠 DRG 的丰度为 64.3 +/- 0.3%。因此，SCN10A 中的 NAGNAG 串联受体在啮齿动物和人类中是保守的，但它的可变使用显然与物种特异性丰度有关。在神经母细胞瘤细胞系 Neuro-2A 中异源表达后，对全细胞膜片钳实验中的人 Na(V)1.8+Q 和-Q 异构体进行分析，未发现剪接事件对通道功能有明显影响。
