论文部分内容阅读
以拟南芥C-8,7甾醇异构酶的氨基酸序列为信息探针搜索GenBank数据库,对高度同源的马铃薯EST序列进行拼接、引物设计和RT-PCR扩增,扩增产物测序结果证实获得一个马铃薯C-8,7甾醇异构酶基因(StSI1)的全长cDNA序列。序列分析结果显示,StSI1全长886bp,包含59bp的5′非编码序列、161bp的3′非编码序列和一个长度为666bp编码221个氨基酸的开放阅读框,分子量约为25kD。氨基酸结构分析显示该蛋白的N端含有一个长度由35个氨基酸残基组成的信号肽,C端成熟肽区域含有典型的类EBP结合域。氨基酸比对分析表明,StSI1与已知C-8,7甾醇异构酶同源性介于32.9%～61.3%之间,与拟南芥AtSI1相似性最高(61.3%)。RT-PCR表达谱分析显示,StSI1在马铃薯的块茎芽眼和表皮组织中均能表达,并且该基因的表达水平受贮藏温度升高和光照增强的正向调节。
The amino acid sequence of Arabidopsis thaliana C-8, 7-sterol isomerase was used as a probe to search the GenBank database. The highly homologous potato EST sequences were spliced, primer designed and RT-PCR amplified. A full-length cDNA sequence of the potato C-8, 7 sterol isomerase gene (StSI1) was obtained. Sequence analysis showed that StSI1 was 886bp in length and contained 59bp 5 ’non-coding sequence, 161bp 3’ non-coding sequence and a 666bp open reading frame encoding 221 amino acids with a molecular weight of about 25kD. Amino acid structural analysis showed that the N-terminal of the protein contains a signal peptide of 35 amino acid residues in length, and the C-terminal mature peptide region contains a typical EBP-like binding domain. Amino acid alignment analysis showed that StSI1 shared 32.9% -61.3% identity with known C-8 and 7-sterol isozymes, and had the highest similarity (61.3%) with Arabidopsis AtSI1. RT-PCR analysis showed that StSI1 was expressed in potato buds and epidermal tissues, and the expression level of StSI1 was positively regulated by the increase of storage temperature and light intensity.