【摘要】 利用RT-PCR方法从矮牵牛(Petunia hybrida)中克隆了MADS盒基因pMADS4,进行了全序列测定。测序结果显示,所得到的基因与发表的序列同源率为100%。该基因长度为910bp,含有一个开放阅读框,编码253个氨基酸残基组成的蛋白,具有典型的植物MADS盒基因的结构,该蛋白序列与玉米(Zeamays)ZAG3、麻竹(Dendrocalamus latiflorus)DlMADS18和拟南芥(Arabidopsis thaliana)AGL6的同源性分别为64%、64%和61%,说明pMADS4是AGL6在矮牵牛中的同源基因,推测它们具有相似的功能,都促进开花并且调节花器官形成。进化树分析显示,AP1/AGL9亚家族分为SEP、AGL6和AP1三个分枝,且AGL6分枝又进一步分为三组,分别与裸子植物、单子叶植物和双子叶植物类群相对应,预测通过分离植物的AGL6同源基因可以准确的判断植物所属类群。通过蛋白预测说明pMADS4蛋白以同源或异源二聚体的形式存在,具有结合DNA的功能。更多还原

【Abstract】 MADS box gene pMADS4 was isolated from Petunia hybrida by RT-PCR. The result of the sequencing showed that this nucleotide sequence of pMADS4 gene has 100% identity with the published sequences. The gene is 910 bp in length, with an open reading frame encoding a 253 amino acid protein, which displayed the structure of typical plant MADS box protein and is close similar to ZAG3 of Zea mays, DlMADS18 of Dendrocalamus lati-florus and AGL6 of Arabidopsis thaliana by 64%, 64% and 61%, respectively. These results suggest that pMADS4 gene be a AGL6 homolog and might have the same function as other AGL6 homologous genes, which might pro-mote flower and regulate floral organ formation. The phylogenetic tree analysis revealed that AP1/AGL9 group was split into SEP, AGL6 and AP1 clades. The AGL6 clade was further divided into three groups which coincided with gymnosperm, dicotyledon and monocotyledon taxa and we put forward a hypothesis to tag species according to the AGL6-like genes. The predicted structure showed that the subunits of pMADS4 protein interact to form both homodimers and heterodimers and the protein dimers have DNA-binding specificities.更多还原