Kreft S, Ravnikar M, Mesko P, Pungercar J, Umek A, Kregar I, Strukelj B
Faculty of Pharmacy, Ljubljana, Slovenia.
Phytochemistry. 1997 Mar;44(6):1001-6. doi: 10.1016/s0031-9422(96)00668-1.
A new cDNA clone coding for an aspartic proteinase inhibitor homologue was isolated from a potato tuber cDNA library. Southern blot analysis was used to study the structural diversity of the aspartic proteinase inhibitor gene family in several species of the Solanaceae. The existence of sequence-homologous genes was confirmed in the genomic DNA of different potato cultivars (Solanum tuberosum L. cv. Désirée, Pentland Squire and Igor), tomato (Lycopersicon esculentum Mill.), aubergine (S. melongena L.) and a wild type of bittersweet (S. dulcamara L.). Northern blot hybridization of total RNA, isolated from leaves under non-stress conditions, of different solanaceous species and of potato tubers showed that the gene transcripts encoding aspartic proteinase inhibitors occur mainly in potato tubers. The presence of several cathepsin D inhibitor isoforms has been detected at the protein level. At least four isoforms were isolated by affinity chromatography on cathepsin D-Sepharose and characterized. Additionally, exogenous treatment of potato plantlets by jasmonic acid (JA) over a wide range of concentrations (0-100 microM) was performed in a stem node culture in vitro. We demonstrated that the expression of aspartic proteinase inhibitor mRNA was drastically induced in potato shoots at concentrations of 50-100 microM JA.
从马铃薯块茎cDNA文库中分离出一个编码天冬氨酸蛋白酶抑制剂同源物的新cDNA克隆。利用Southern印迹分析研究了茄科几种植物中天冬氨酸蛋白酶抑制剂基因家族的结构多样性。在不同马铃薯品种（马铃薯栽培种Désirée、Pentland Squire和Igor）、番茄（番茄栽培种Mill.）、茄子（茄子栽培种L.）和野生龙葵（龙葵栽培种L.）的基因组DNA中证实了序列同源基因的存在。对从非胁迫条件下的叶片中分离得到的不同茄科植物以及马铃薯块茎的总RNA进行Northern印迹杂交，结果表明编码天冬氨酸蛋白酶抑制剂的基因转录本主要存在于马铃薯块茎中。在蛋白质水平上检测到了几种组织蛋白酶D抑制剂同工型。通过组织蛋白酶D-Sepharose亲和层析分离并鉴定了至少四种同工型。此外，在体外茎节培养中，用不同浓度（0-100 microM）的茉莉酸（JA）对马铃薯幼苗进行了外源处理。我们证明，在50-100 microM JA浓度下，马铃薯芽中天冬氨酸蛋白酶抑制剂mRNA的表达被显著诱导。
