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目的从大鼠胰腺β细胞中，克隆ＬＶＡ钙通道（即Ｔ－型钙通道）基因，并鉴定其一级结构的特征。方法用ＲＴ－ＰＣＲ，３’－ＲＡＣＥ及５’－ＲＡＣＥ法，从总ＲＮＡ中克隆Ｔ－型钙通道全长基因；用ＤＮＡ序列测定与ＤＮＡ步移实验，分析基因一级结构及外显子剪接。结果克隆了Ｔ－型钙通道的全长结构基因，命名为α１Ｇ－ＩＮＳ。该基因由６８６４个碱基组成，编码２２８８个氨基酸，与从神经组织中克隆的钙通道α１Ｇ相比较：在氨基酸水平上有９６．３％的同源性，在４个结构域的跨膜区内的氨基酸及Ⅰ、Ⅱ结构域间的胞内环链部分的氨基酸具有高度保守性；两者间具有３个明显不同的结构区段，基因组ＤＮＡ步移法分析表明，这种差异是由于ｍＲＮＡ前体的不同剪接所致。此外，尚有１０个氨基酸替代散在于分子内其它区域，这种替代是由于基因突变造成的。结论成功地从大鼠胰腺β细胞中，克隆到ＬＶＡ钙通道基因中的１个新亚型（ｉｓｏｆｏｒｍ）α１Ｇ－ＩＮＳ，对深入研究钙离子所涉及的许多重要的基本生命过程有着重要的意义。
Objective To clone the LVA calcium channel (ie, T-type calcium channel) gene from rat pancreatic β-cells and characterize its primary structure. Methods The full-length T-type calcium channel cDNA was cloned from total RNA by RT-PCR, 3’-RACE and 5’-RACE. DNA sequencing and DNA walking were used to analyze the primary structure and exon Splicing. Results The full-length structural gene of T-type calcium channel was cloned and named α1G-INS. This gene, consisting of 6864 bases, encodes a protein of 2288 amino acids, compared with the calcium channel α1G cloned from neural tissue: 96.3% homology at the amino acid level, in the transmembrane region of the four domains Amino acids within the intracellular I and II domains are highly conserved among the amino acids in the I and II domains. There are three distinct structural segments between them, and the step by step analysis of the genomic DNA shows that the difference is due to the mRNA Different precursors due to splicing. In addition, there are still 10 amino acid substitution scattered in other regions of the molecule, this alternative is due to genetic mutations. Conclusion The successful cloning of isoform α1G-INS from rat pancreatic β-cell into the calcium channel gene of LVA is of great significance for further study of many important basic life processes involved in calcium ion.