玉米DEAD-box RNA解旋酶基因的克隆及分析

Cloning and Characterization of DEAD-box RNA Helicases Gene from Maize (Zea mays L.)

DEAD-box RNA解旋酶参与RNA转录、前体mRNA剪切、核糖体发生、核质运输、蛋白质翻译、RNA降解等重要的生命活动.根据本室在S-Mo17Rf3Rf3cDNA芯片研究中,检测到花粉发育后期RNA解旋酶上调表达的结果,应用RACE技术从S-Mo17Rf3Rf3花粉中克隆得到该RNA解旋酶基因全长cDNA,命名为ZmRH2并在GenBank注册登记(DQ327709).序列分析表明该cDNA全长1652bp,从第163bp开始到1386bp含有一个开放阅读框,编码407个氨基酸.其编码的蛋白质具有DEAD-boxRNA解旋酶特有的9个保守模体,与水稻、拟南芥和豌豆中的DEAD-boxRNA解旋酶的氨基酸序列存在着很高的同源性.RT-PCR分析表明,该基因在近等基因系S-Mo17Rf3Rf3和S-Mo17rf3rf3的叶、根、和雌穗中的表达没有差异,但在花丝和花粉中有明显差异.

DEAD-box RNA helicases are involved in various aspects of RNA metabolism, including RNA transcription, premRNA splicing, ribosome biogenesis, nucleocytoplasmic transport, translation and RNA decay. According to maize S-Mo17^Rf3Rf3 cDNA microarray data, an RNA helicases was found to be upregulated in the later stage of pollen development. Full-length cDNA of this RNA helicases, named ZmRH2 was cloned （GenBank accession number： DQ327709） in maize S-Mo17^Rf3Rf3 pollen using RACE. cDNA sequencing indicated ： the full length of ZmRH2 cDNA is 1 652 bp, which contained an open reading frame encoding 407 amino acids from 163th to 1 386th positions. The encoding amino acid sequence of ZmRH2 consisted of nine conserved motifs that characterize DEAD-box RNA helicases and showed highly homology with DEAD-box RNA helicases of Oryza sativa, Arabidopsis thaliana and Pisum sativum. RT-PCR showed that expression level of ZmRH2 showed little difference in the leaf, root and ear between one pair of maize NIL （ Near Isogenitic lines） of S-Mo17^Rf3Rf3 and S-Mo17^rf3f3 , and the expression of ZmRH2 differed significantly in silk and pollen between S-Mo17^Rf3Rf3 and S-Mo17^rf3rf3.