芜菁BrrCIPAS8基因的克隆,序列分析与功能预测

Molecular Cloning, Sequence Analysis and Functional Prediction of BrrCIPAS8 Gene in Turnip

镉(Cd)诱导蛋白AS8基因(cadmium-induced protein AS8, CIPAS8)广泛存在于植物中,可能参与了植物对Cd等金属离子的响应过程,但目前关于它的功能报道很少。本研究从芜菁(Brassica rapa var. rapa,Turnip)中克隆得到了BrrCIPAS8基因的CDS序列,其全长开放阅读框为528 bp,编码175个氨基酸。预测的蛋白分子量为18.7 kD,理论等电点为8.35,不稳定系数为20.49。蛋白序列分析显示BrrCIPAS8蛋白有2个保守的跨膜结构域,亚细胞定位检测发现其定位于细胞质膜。基因表达量分析表明BrrCIPAS8基因主要在芜菁叶中表达,并随着植物生长有上调表达趋势。此外,BrrCIPAS8基因对多种金属离子胁迫有响应,Zn、Cu和Mn能诱导芜菁叶中BrrCIPAS8基因的表达,Co和Cd会抑制叶中BrrCIPAS8基因的表达。说明该基因可能参与了芜菁吸收和转运金属离子。本研究将促进对植物CIPAS8基因的认识,为深入研究BrrCIPAS8基因的功能提供理论依据。

The cadmium-induced protein AS8(CIPAS8) gene is widely found in plants, which may be related to the absorption and transport of heavy metal ions, such as Cd, but its function is rarely reported. In this study, the CDS sequence of BrrCIPAS8 was cloned from turnip(Brassica rapa var. rapa). The full-length open reading frame of BrrCIPAS8 was 528 bp, encoding a 175 amino acid peptide. The molecular weight, isoelectric point and instability coefficient of the predicted protein were 18.7 k D, 8.35 and 20.49, respectively. Sequence alignment showed that the BrrCIPAS8 protein contained two transmembrane domains, and it was localized in the cell plasma membrane by subcellular analysis. The qRT-PCR results indicated that the BrrCIPAS8 gene was mainly expressed in the leaves of turnip and it showed significant up-regulated expression trend as plant grew. In addition, it was found that BrrCIPAS8 gene could response to various metal ions stress. Zn, Cu and Mn induced the expression of BrrCIPAS8 in turnip leaves, while Co and Cd inhibited its expression. The results indicated that BrrCIPAS8 gene might be involved in the absorption and transport of metal ions in turnip. This study would be helpful to understand the roles of CIPAS8 gene in plants and provide theoretical basis for further study on the function ofBrrCIPAS8 gene.