家蚕核糖体蛋白L7基因cDNA序列的克隆和分析

为了研究家蚕孤雌生殖的调节机制,应用二维凝胶电泳(2DE)技术分离正常生殖的家蚕卵与孤雌生殖家蚕卵的差异蛋白质,在蛋白质水平上筛选与家蚕孤雌生殖过程相关的重要蛋白质.利用MALDI-TOF-TOF MS分析这些差异蛋白,获得了大量小肽的序列特征.BLAST搜索本实验室构建的cDNA文库,获得了1个与家蚕孤雌生殖相关的核糖体蛋白L7基因.根据已有的cDNA文库,采用RACE方法克隆得到该核糖体蛋白基因的全长cDNA.利用生物信息学的方法和工具,对这个基因在核酸水平和蛋白质水平分别作了详细的分析和讨论并进行蛋白结构预测.结果表明,核糖体L7基因的cDNA全长为858 bp,编码区包含6个外显子,共编码268个氨基酸残基,蛋白的疏水性平均值为-0.586,分子量大小为30 kD,极性的最大值为 39.616,最小值为0.451,等电点为10.52.分子系统分析显示,该蛋白与Apis, Lysiphlebus 和Meladema中的核糖体蛋白L7具有较高的同源性.

Cloning and Characterization of cDNA for Ribosomal Protein L7 of Bombyx mori

To elucidate the regulatory mechanism of Bombyx mori parthenogenesis, the two-dimension gel electrophoresis (2DE) technique was adopted to obtain the differential protein spots between B. mori eggs of normal and parthenogenetic propagation. Then, the protein spots related parthenogenesis was screened. After these spots were analyzed by MALDI-TOF-TOF- MS, we obtained many protein and peptide sequences. These sequences were searched by BLAST against B. moricDNA librarythat was constructed in our laboratory, we found a B. mori ribosomal protein L7. We cloned the full length cDNA sequence of ribosomal protein L7 via RACE method. The cDNA and deduced protein sequence were analyzed by bioinformatics. The results showed that the full-length cDNA sequence consists of 858 bases,including six exons and encoding for 268 amino acid residues. The average value of hydrophobicity predicted is -0.586; the molecular weight of the deduced protein is 30 kD; the maximum value of polarity is 39.616; the minimum value of polarity is 0.451; and the pI is 10.52. Molecular phylogeny tree showed that the ribosomal protein L7 of B. mori shares high homology with the ribosomal proteins L7 of Apis, Lysiphlebus and Meladema.