西伯利亚蓼硫堇基因的克隆和序列分析

根据西伯利亚蓼抑制消减文库(SSH)中获得的硫堇(THI)基因的部分序列,应用RACE技术克隆了具有PolyA的全长cDNA序列。基因全长789bp,5'非翻译区90bp,3'非翻译区276bp,开放阅读框编码140个氨基酸。序列分析表明,该编码蛋白与大多数植物THI蛋白前体高度相似,N端具24个氨基酸的信号肽,中间46个氨基酸为成熟THI部分,C端的70个氨基酸为酸性多肽部分。西伯利亚蓼THI蛋白与丹参等双子叶植物THI蛋白有较高的同源性,具保守的植物THI标签序列C-C-X(5)-R-X(2)-FY]-X(2)-C。此成熟THI蛋白带正电荷,偏碱性,推定可能具有抗病原微生物活性,为一种新的植物THI蛋白,GenBank登录号为DQ981482。

Gene Cloning and Sequence Analysis of Thionins from Polygonum sibiricum Laxm

A partial sequence of a thionins (THI) gene was obtained from a random clone in Polygonum sibiricum SSH library and THI was cloned by using rapid amplification of cDNA end (RACE) technology. The acquired gene was 789 bp in full length, including 5' untranslated region of 90 bp, 3' untranslated region of 276 bp with Poly A, and an open reading frame (ORF) encoding 140 amino acid. Sequence analysis indicated that the protein, such as most of the plant THI, was a precursor which could be divided into three distinct domains, including an amino-terminal (N-terminal) signal peptide, a mature THI and a carboxy-terminal (C-terminal) acidic domain, which were composed of 24, 46 and 70 amino acid respectively. THI was found to be highly homologous with that from other dicotyledon. All of them possessed a conserved plant THI signature sequence of "C-C-X(5)-R-X(2)-FY]-X(2)-C" . The mature THI had positive charge and showed slightly high basic. As result, it was possibly involved in antimicrobial activity and was identified as a new plant THI. The gene accession nucleotide sequence number in GenBank was DQ981482.