花生果种皮特异表达基因AhPSG13的克隆和表达研究

Molecular cloning and expression of pericarp and testa specific expression gene AhPSG13

为了克隆在花生果种皮中特异表达的基因,本实验从花生果皮种仁抑制消减文库中筛选出一个277bp的EST序列并进行研究,通过构建花生果皮全长cDNA文库,获得此目的基因G13的全长为1369bp,开放阅读框从第28个碱基始至1122个碱基止,预测分子量为39865.59,等电点5.73。生物信息学分析表明该基因编码的蛋白具有4个跨膜结构域和多个活性位点,可能与细胞内DNA转录有关;该蛋白与多种豆科作物的半胱氨酸蛋白酶具有较高同源性,推测为花生半胱氨酸蛋白酶相关基因;RT-PCR研究该基因表达,结果显示该基因在果种皮中特异表达,于30d果皮中表达量最大。本研究克隆的AhPSG13基因序列已经登陆到GenBank,登录号为FJ475061。

In order to clone the specific expression gene in pericarp and testa of peanut,a 277bp EST isolated from suppression subtractive hybridization of pericarp and testa was further studied. We screened the full length of the gene from a testa cDNA library. The gene named AhPSG13 was 1 369bp and its open reading frame was from 28bp to 1 122bp. The putative protein MW was 39 865.59 and the isoelectric point was 5.73. The structure analysis showed that the protein contained four cross-membrane regions and many active loci,which suggested its transcript function in cell. This protein was highly homologous with cysteine proteinase of some other legume crops and we assumed that it might have been related with the synthesis of cysteine proteinase in peanut. Expression analysis by RT-PCR revealed that this gene was specially expressed in pericard and testa,and mostly expressed in pericarp of 30 days. The gene we cloned in the research has been submitted to GenBank （GenBank Accession Number FJ475061）.