野桑蚕钠离子通道蛋白基因Bmmpara的克隆与选择性剪接

昆虫的钠离子通道蛋白是许多神经毒性药物的作用靶标。根据家蚕钠离子通道蛋白基因(GenBank登录号:EU688970)序列设计引物,分段RT-PCR克隆了野桑蚕钠离子通道蛋白基因Bmmpara(GenBank登录号:EU688972)。序列分析表明,Bmmpara基因的cDNA长5553bp,编码1851个氨基酸,与家蚕基因组序列比对,存在34个外显子,其中第2、22、27外显子存在选择性剪接。根据Bmmpara序列和家蚕基因组序列设计引物,采用PCR方法克隆到3段野桑蚕基因组序列,长度分别为1632、536和3220bp。进一步将Bmmpara编码氨基酸序列与野桑蚕基因组比对,发现有a(ENDLGRTKKKK)、b(GL-KAALCGRCVSS)、c(SLINFVAALCGAGGIQAFKTMRTLRALRPLRAMSRMQGMRV)3个选择性微外元,可能存在6种选择性剪接,构成野桑蚕钠离子通道蛋白不同亚型。

Cloning and Selective Splicing of Sodium Channel Protein Gene of Bombyx mandarina

Insect sodium channel protein is the molecular targets for a broad range of neurotoxins. With the special primers designed according to the partial sequence of Bombyx mori sodium channel protein gene ( GenBank No. EU688970),the sodium channel protein gene of Bombyx mandarina Bmmpara (GenBank No. EU688972) was cloned by RT-PCR. Sequence analysis indicated that Bmmpara cDNA is 5 553 bp,which encodes 1 851 amino acids. Comparison with Bombyx mori genome sequence revealed that 34 exons exist in Bmmpara cDNA and exons 2,22 and 27 might be selectively spliced out. With primers designed according to the sequences of Bmmpara and Bombyx mori genome, three Bombyx mandarina genomic sequences were cloned by PCR,which was 1 632 bp,536 bp and 3 220 bp long,respectively. Further comparison between the encoded amino acids of Bmmpara with Bombyx mandarina genomic sequences suggested that Bmmpara has three optional micro-exons including a (ENDLGRTKKKK),b (GLKAALCGRCVSS) and c (SLINFVAALCGAGGIQAFKTMRTLRALRPLRAMSRMQGMRV). And six kinds of selective splicing might result in different subtypes of sodium channel protein in Bombyx mandarina.