Liu Z, Chung I, Dong K
Department of Entomology, Michigan State University, 106 Center for Integrated Plant Systems, East Lansing, MI 48824, USA.
Insect Biochem Mol Biol. 2001 Apr 27;31(6-7):703-13. doi: 10.1016/s0965-1748(00)00178-8.
Voltage-gated sodium channels are integral transmembrane proteins responsible for the rapidly-rising phase of action potentials in most excitable cells. In mammals, the functional diversity and wide distribution of sodium channel proteins in various tissues and cell types are achieved mainly by selective expression of many distinct sodium channel genes. In the model insect, Drosophila melanogaster, however, only one confirmed sodium channel gene, para, and one putative sodium channel gene, DSC1, are known. We cloned and sequenced a DSC1 ortholog, BSC1, from the German cockroach, Blattella germanica. We found that the BSC1 transcript was present in a wide range of tissues, including nerve cord, muscle, gut, fat body and ovary, whereas the para transcript was detected only in nerve cord and muscle. Moreover, different tissues contained distinct alternatively spliced variants of BSC1, and two muscle-specific spliced variants are predicted to encode truncated proteins with only the first two of the four homologous domains. Therefore, alternative splicing and expression of distinct splicing variants in functionally different tissues may be a major mechanism by which insects increase BSC1 channel diversity in neuronal and non-neuronal tissues.
电压门控钠通道是大多数可兴奋细胞中动作电位快速上升期的重要跨膜蛋白。在哺乳动物中，钠通道蛋白在各种组织和细胞类型中的功能多样性和广泛分布主要通过许多不同钠通道基因的选择性表达来实现。然而，在模式昆虫黑腹果蝇中，已知只有一个已确认的钠通道基因para和一个推定的钠通道基因DSC1。我们从德国小蠊中克隆并测序了DSC1的直系同源基因BSC1。我们发现BSC1转录本存在于广泛的组织中，包括神经索、肌肉、肠道、脂肪体和卵巢，而para转录本仅在神经索和肌肉中检测到。此外，不同组织含有不同的BSC1可变剪接变体，并且预测有两种肌肉特异性剪接变体编码仅具有四个同源结构域中前两个结构域的截短蛋白。因此，在功能不同的组织中可变剪接和不同剪接变体的表达可能是昆虫增加神经元和非神经元组织中BSC1通道多样性的主要机制。
