巴西橡胶树线粒体50S核糖体蛋白L21 cDNA的克隆与分析

Cloning and Analysis of a cDNA Encoding Mitochondrial 50S Ribosomal Protein L21 from Hevea brasiliensis Muell.Arg.

在橡胶生产中,"死皮"生理综合症严重制约了橡胶树(Hevea brasiliensis)单产的提高。在早期构建的差减文库中,筛选到一条在死皮植株中下调表达的基因片段,该片段编码的蛋白与线粒体50S核糖体蛋白L21(mRPL21)同源。通过ESTs序列拼接和RT-PCR,获得一条853 bp的cDNA序列(命名为HbmRPL21,GenBank登录号为HM800425),该序列包含一个完整的开放读码框,编码271个氨基酸,理论分子量为30.52 kD,等电点为8.40。同源比对表明,植物和动物界间mRPL21序列差异很大,而植物界内则相对比较保守。生物信息学分析表明,HbmRPL21是一个包含Ribosomal_L21p保守结构域的线粒体定位蛋白。

Tapping panel dryness（TPD） syndrome,a phenomenon with tapping incision blocked partly or entirely during latex exploiting,has become an important factor limiting rubber production for its causing great losses.In preliminary studies,a sequence encoding a deduced protein with high similarity to mitochondrial 50S ribosomal protein L21（mRPL21）,which is upregulated in the latex of TPD-affected rubber trees,was isolated by suppression subtractive hybridization（SSH）.Combining ESTs assembling and RT-PCR,a cDNA called HbmRPL21 with GenBank accession number of HM800425 was cloned.The sequence contains 853 bp in length with an open reading frame（ORF）,which encodes a deduced polypeptide of 271 amino acids with a theoretical molecular weight（Mw） of 30.52 kD and isolectric point（pI） of 8.40.Similarity search reveals high amino acid sequence identity of mRPL21 from plants,but diversity of that between plant and animal kingdom.Bioinformatics analysis suggests HbmRPL21 is a mitochondrion-targeted protein with a conserved domain of ribosomal_L21p involving translation.