Loughney K, Kreber R, Ganetzky B
Laboratory of Genetics, University of Wisconsin, Madison 53706.
Cell. 1989 Sep 22;58(6):1143-54. doi: 10.1016/0092-8674(89)90512-6.
Previous behavioral, electrophysiological, pharmacological, and genetic studies of mutations of the para locus in Drosophila melanogaster suggested that these mutations alter the structure or function of sodium channels. To identify the protein encoded by this gene and to elucidate the molecular basis of the mutant phenotypes, genomic DNA from the para locus was cloned. Mutational lesions in nine different para alleles were mapped and found to be distributed over a region of 45 kb. Analysis of cDNAs revealed that the para locus comprises a minimum of 26 exons distributed over more than 60 kb of genomic DNA. The nucleotide sequence of the complementary DNA predicts a protein whose structure and amino acid sequence are extremely similar to those of vertebrate sodium channels. The results support the conclusion that para encodes a functionally predominant class of sodium channels in Drosophila neurons. Furthermore, the para transcript appears to undergo alternative splicing to produce several distinct subtypes of this channel.
先前对黑腹果蝇para基因座突变进行的行为学、电生理学、药理学及遗传学研究表明，这些突变会改变钠通道的结构或功能。为了鉴定该基因编码的蛋白质并阐明突变表型的分子基础，对para基因座的基因组DNA进行了克隆。绘制了九个不同para等位基因中的突变位点图谱，发现它们分布在45 kb的区域内。对cDNA的分析表明，para基因座至少包含26个外显子，分布在超过60 kb的基因组DNA上。互补DNA的核苷酸序列预测出一种蛋白质，其结构和氨基酸序列与脊椎动物钠通道的结构和氨基酸序列极为相似。这些结果支持了para基因在果蝇神经元中编码功能上占主导地位的一类钠通道的结论。此外，para转录本似乎会发生可变剪接，从而产生该通道的几种不同亚型。
