南方红豆杉bHLH基因克隆与序列分析

Cloning and Sequence Analysis of b HLH Gene from Taxus chinensis var. mairei

以南方红豆杉为试材,利用RT-PCR方法从南方红豆杉c DNA中克隆了一个b HLH转录因子——Tc MYC,Gen Bank注册号为KC878013。通过生物信息学分析,发现该基因全长1 959 bp,编码一个650个氨基酸残基的亲水蛋白;Tc MYC相对分子量为71.4 k D,等电点p I为4.87。推测所克隆Tc MYC基因编码的蛋白定位于细胞核中,含有一个螺旋—环—螺旋结构,与东北红豆杉、葡萄和烟草的MYC基因编码的蛋白序列一致性分别为98%、45%和44%,进化树分析表明同科属植物的MYC转录因子归为一类,红豆杉的MYC与其他草本被子植物的MYC转录因子亲缘关系都较远。在茉莉酸甲酯诱导的红豆杉细胞中,Tc MYC基因表达呈现略微下降趋势,推测Tc MYC可能负向调控紫杉醇生物合成,为利用分子手段调控紫杉醇的生物合成提供了理论基础。

We cloned a new bHLH transcription factor named TcMYC by RT-PCR technology from Taxus chinensis var. mairei, with GenBank accession number KC878013. By the Blast analysis, it belongs to MYC subgroup. By the bioinformatic analysis, the sequences length of TcMYC is 1 959 bp encoding one opening reading frame with 650 amino acid residues with hydrophilic property. The molecular weight of TcMYC is 71.4 kD, and the theoretical pI is 4.87. The predicated protein TcMYC is localized to cell nucleus, as well as contained one helix-loop-helix structure. By Blast and multiple sequences alignment analysis, TcMYC shares 98%, 45% and 44% identity with Taxus cuspidata, Vitis vinifera and Nicotiana tabacum, respectively. The constructed tree shows that the MYC transcription factors of the plants belonging to the same family clustered together, and as Taxus is a gymnosperms plant, TcMYC and TaMYC are not clustered with other angiosperms plants. The expression of TcMYC is a little declined in Methyl jasmonate induced Taxus cell culture. TcMYC may regulate Taxol biosynthesis in negative.