玉米ZmCPB1基因的克隆、表达及生物信息学分析

从玉米中克隆ZmCPB1基因的cDNA序列,全长1 446 bp,编码481个氨基酸,蛋白质理论分子量为54.05 KD,等电点为8.59。生物信息学分析表明,ZmCPB1蛋白N端有跨膜结构,是跨膜蛋白。蛋白质二级结构含有48.44%的α-螺旋、4.99%的β-转角、10.60%的延伸链以及35.97%的无规则卷曲,该蛋白定位于内质网中。序列比对结果显示,ZmCPB1蛋白含有与子粒发育相关的保守区VKFVHRKALK。系统进化树分析表明,该蛋白与高粱、谷子、水稻和大麦的同源蛋白亲缘关系最近,同属一个亚支。实时荧光定量PCR分析ZmCPB1基因的表达模式,结果表明,ZmCPB1基因在3叶期的根、茎、叶以及雄穗和苞叶中表达量较低,在雌穗中的表达量较高。在玉米子粒发育的不同时期,ZmCPB1基因的表达量呈现一定的规律变化,在授粉后0～10 d,表达量逐渐达到最高峰,之后开始下降,在授粉15 d后降到较低水平。初步判断ZmCPB1基因与玉米子粒早中期发育有关。

Cloning, Expression and Bioinformatics Analysis of ZmCPB1 Gene for Regulating the Kernel Development of Maize

A maize gene named ZmCPB1 was cloned from maize Qi319 inbred lines in this study. The full-length cDNA of ZmCPB1 was 1 446 bp that encoded a protein of 481 amino acids with predicted molecular weight of 54.05 KD and a theoretical isoelectric point of 8.59. Bioinformatics analyses showed that ZmCPB1 was a transmembrane protein with a membrane-spanning domain in N-Terminal. The secondary structure of ZmCPB1 protein contained 48.44% of alpha helix, 4.99% of beta turn, 10.60% of extended strand and 35.97% of random coil. The result of Plant-mPLoc prediction indicated that ZmCPB1 protein was located in endoplasmic reticulum. Sequence alignment showed that ZmCPB1 contained a highly conserved region of VKFVHRKALK. The phylogenetic analysis revealed ZmCPB1 protein was the highest related to homologous proteins of Sorghum bicolor, Setaria italica, Oryza sativa and Hordeum vulgare, which belonged to the same branch. Furthermore, quantitative Real Time Polymerase Chain Reaction(qRT-PCR) assay was performed to analyze the expression pattern of ZmCPB1 in different tissues and developmental stages of maize. The results showed that the expression level of ZmCPB1 was lower in root, stems, leaves and bract, but higher in ear. At different stages of maize grain development, the expression pattern of ZmCPB1 showed a certain regular change. The expression of ZmCPB1 increased continually from one day to ten days after pollination, and reached the highest level at the 10th day, then decreased significantly. These results demonstrated that ZmCPB1 is involved in maize grain development, which laid a foundation for further research on the biological function of ZmCPB1.