越南油茶HMGCR基因的克隆及表达分析

Cloning and Expression Analysis of HMGCR Gene in Camellia vietnamensis

为研究越南油茶(Camellia vietnamensis T.C.Huang ex Hu)中HMGCR(3-羟基-3-甲基戊二酰辅酶A还原酶)基因的分子作用机制,本研究采用同源克隆得到HMGCR基因全长并命名为CvHMGCR,对其进行生物信息学分析及表达模式研究。结果表明,CvHMGCR全长1800 bp,包括一个1770 bp完整的开放阅读框,编码589个氨基酸,与茶树(Camellia sinensis)、毛柄连蕊茶(Camellia fraterna)、喜树(Camptotheca acuminata)、风铃辣椒(Capsicum baccatum)和三七(Panax notoginseng)的HMGCR蛋白序列相似度均在75%以上,系统发育树显示Cv HMGCR与茶树(Camellia sinensis)、毛柄连蕊茶(Camellia fraterna)和喜树(Camptotheca acuminata)的HMGCR蛋白序列聚为一支。预测其蛋白分子质量为63.1kD,理论等电点为6.37,有两个跨膜螺旋区,属于不稳定疏水性蛋白。序列比对分析表明,CvHMGCR有4个典型的HMGCR保守基序,即2个HMG-CoA结合基序和2个NADP(H)结合基序。CvHMGCR基因在种子不同成熟期及植株根叶中均有表达,其中种子在九月的表达量显著高于其他月份;而对于不同组织部位中,叶的表达量最高。本研究结果为越南油茶次生代谢产物合成研究提供理论依据。

In order to study the molecular mechanism of the 3-hydroxy-3-methyl pentamidase A reductase(HMGCR)gene in Camellia vetnamensis T.C.Huang ex Hu,this study used homologous cloning to obtain the full-length of HMGCR gene,named CvHMGCR,and conducted bioinformatics analysis and expression pattern research on it.The results showed that the total length of CvHMGCR 1800 bp,including a 1770 bp open reading frame(ORF),encoding 589 amino acids,which had above 75%similarity with the HMGCR protein sequences of C.sinensis,C.fraterna,Camptotheca cuminata,Capsicum baccatum and Panax noginseng.The molecular weight of CvHMGCR protein was predicted to be 63.1 kD,and the PI was 6.37.The enzyme has two transmembrane helix regions,which belongs to unstable hydrophobic protein.Sequences comparison analysis showed that CvHMGCR had four highly conservative motifs,namely two HMG-CoA binding motifs and two NADP(H)binding motifs.The CvHMGCR gene was expressed in different maturity stages of seeds and different tissue parts of the plants,with the higher CvHMGCR expression of seeds in September than in other months.For different parts of tissue,leaf had the highest expression of CvHMGCR.The results of this study provide a theoretical basis for the synthesis of secondary metabolites of C.vietnamensis.