濒危药用植物青天葵器官大小调控基因EBP1的克隆与分析

Cloning and Analysis of an Organ Size Regulator Gene EBP1 from Nervilia fordii (Hance) Schtlr.

表皮生长因子受体3结合蛋白(ErbB3 binding protein,EBP1)是植物器官大小生长的关键调控因子。本研究应用RACE-PCR技术从濒危药用植物青天葵(Nevilia fordii(Hance)Schltr.)中克隆获得EBP1编码基因并命名为NfEBP1。该基因全长为1 188 bp(Genbank登记号JN854245),编码395个氨基酸。生物信息学分析表明,NfEBP1蛋白分子量为43.4 kD,等电点为6.12,整体表现为亲水性。NfEBP1不含信号肽、叶绿体转运肽或线粒体靶向肽,整体位于细胞膜外;其二级结构由21个α-螺旋、21个延伸链、18个β-转角和28个随意卷曲构成。NfEBP1含有PA2G4细胞增殖功能域,与其他植物EBP1有着高度的同源性,均归属APP_MetAP超级家族。NfEBP1在青天葵不同组织均有表达,相对表达量以叶片最高,球茎次之,叶柄则最低。本研究成功克隆青天葵EBP1基因并分析其在青天葵不同组织的表达水平,为下一步利用该基因促进青天葵器官生长研究提供了基础数据。

ErbB3 binding protein is a key regulator of organ size in plants. An EBP1 gene was cloned from N. fordii by RACE-PCR and named as NfEBP1 （Genbank accession number JN854245）. The ORF of NfEBP1 contained 1 188 base pairs encoding 395 amino acids. The molecular weight of NfEBP1 protein was 43.5 kD, the isoelectric point was 6.12, and its overall structure exhibited hydrophilic. NfEBP1 contains no signal peptide, chloroplast transit peptide, mitochondrial targeting peptide, and located entirely outside cell membrane. The predicted secondary structure of NfEBP1 was composed of 21 a-helixes, 21 extend strands, 18 β-turuers and 28 random coils. NfEBP1 showed high homology with EBP1 protein from other plants, and possessed a functional domain PA2G4. NfEPB1 was ubiquitously expressed in all tissues of N. fordii, and the relative expression level reached the highest in leaf, and the lowest in petiole. This study provided a firmfoundation for promoting organ size ofN. fordii by manipulating EBP1.