烟草病毒抗性相关基因SGT1的电子克隆及序列分析

Cloning and Sequence Analysis of Tobacco Anti-virus Resistance Related Gene SGT1

为研究烟草病毒抗性信号通路基因(SGT),以番茄(Solanum lycopersicum)信号通路基因slSGT1-2为探针,利用电子克隆的方法从栽培烟草品种珊西烟中克隆信号通路基因,并对其进行了序列分析。结果表明:成功克隆到的信号通路基因cDNA序列1 041bp,包含完整的开放阅读框,编码346个氨基酸,具有23kD类SGT1蛋白结构域(p23-SGT1like domain)。分子式为C1719H2707N441O509S16,分子量为38 209Da,理论等电点为5.35,属于稳定蛋白;在275~308氨基酸处形成1个跨膜区,N端以螺旋为主,C端在螺旋中出现折叠。NtSGT1氨基酸序列与番茄SGT1-2基因编码蛋白一致性达到90%,而与已报道的野生烟基因相比C端区域缺少部分保守结构域。说明,NtSGT1是烟草中未报道的病毒抗性信号通路基因。

To study on the gene SGT, by the method of in silico cloning, the sequence of NtSGT1 （Nicotina tabacum SGT1 gene）, a putative important signal transduction factor, was obtained successfully from tobacco cultivar Shanxi using Solanum lycopersicum SGTI-2 gene sequence as probe. Sequence analysis showed that the in silico cloned cDNA had a complete open reading frame, and encoded a protein composed of 346 amino acid residues with TPR and SGTl-like conserved domain. Multiple alignment results showed that the sequence encoded by NISGT1, lack of the C-terminus counterpart aligned with NbSGT1 sequence, sharing 90~ identity with Solanum lycopersicum homologue gene. The alignment and evolution a^alysis confirmed that the NtSGT1 could be an unpublished important gene which related with resistance signal transduction.