Abstract:

Objective To clone and preliminarily analyze the full?length cDNA encoding retinoid X receptor 2（RXR2）from Schistosoma japonicum. Methods The rapid amplification cDNA ends （RACE） was applied to get a full?length cDNA encoding ret? inoid X receptor 2 from S. japonicum（SjRXR2） . The transcription of SjRXR2 was detected by real?time PCR. By bioinformatical technology，the gene structure was analyzed and the antibody epitope was predicted. The polyclonal antibodies were raised in mice immunized with the synthesis peptide. Western blot was applied to detect its expression in the worm. Results The full?length cD? NA of SjRXR2 was 5 960 bp and contained an open reading frame encoding a 1 435 amino acid which had a predicted molecular weight 159 kDa. Bioinformatical analysis indicated that SjRXR2 had a highly conserved DNA binding domain（DBD）and a moder? ate conserved ligand binding domain（LBD） . The relative mRNA （s）of SjRXR2 with higher expressions at Day 21 and 42 were evaluated in five different S. japonicum developmental stages. The Western blot analysis showed that polyclonal antibodies were able to specifically recognize the protein with molecular around 150 kDa from the extract of S. japonicum. Conclusion A full ? length cDNA encoding retinoid X receptor 2（RXR2）from S. japonicum is obtained which provides preliminary information for fur? ther investigation of SjRXR2 functions in S. japonicum.

Key words: Schistosoma japonicum；Retinoid X receptor 2（RXR2）；Rapid amplification cDNA ends（RACE）；Nuclear re? ceptor

摘要：

目的 克隆编码日本血吸虫视黄酸X受体2 （SjRXR2） 蛋白的全长cDNA， 并对其进行初步研究。 方法 利用cD? NA末端快速扩增技术 （RACE） 获得SjRXR2蛋白全长编码cDNA。利用生物信息学技术， 对基因结构进行初步分析。利用实时荧光定量 （Real?time） PCR技术对该基因在日本血吸虫不同时期虫体中的转录情况进行分析。应用在线抗体表位预测软件获得SjRXR2配体结合区抗原性较强的一个多肽序列， 合成该多肽片段， 并免疫小鼠制备抗血清。利用Western blot技术分析该蛋白在日本血吸虫中的表达。 结果 采用RACE技术成功获得了SjRXR2 蛋白全长编码cDNA， 总长度为5 960 bp，其完整开放阅读框为4 308 bp， 编码1 435个氨基酸， 预测分子量为159 kDa。生物信息学分析表明该基因编码的蛋白质序列具有核受体家族2的典型结构域特征， 且与曼氏血吸虫RXR2有较高的相似性。Real?time PCR分析表明， 该基因在 21、 42 d龄日本血吸虫虫体内有较高的转录水平。Western blot分析表明， 小鼠SjRXR2多肽免疫血清可特异性识别日本血吸虫虫体150 kDa蛋白。 结论 成功获得了编码SjRXR2蛋白的全长cDNA， 并制备了针对该蛋白的特异性多克隆抗体， 为进一步研究该蛋白的功能奠定了基础

关键词: 日本血吸虫； 视黄酸X受体2； cDNA末端快速扩增技术； 核受体