【作者】 王莹；

【导师】 张炜；

【作者基本信息】 南京农业大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 前期研究以盐敏感水稻品种武运粳8号为材料,研究了盐胁迫对其根尖细胞程序性死亡(PCD)的诱导。本文通过线粒体蛋白质组双向电泳证明线粒体热激蛋白70(mtHSP70)受PCD诱导,且PCD过程中呼吸链复合物Ⅰ表达量下降。进一步对mtHSP70进行了生物信息学分析,并在转录和翻译水平研究了mtHSP70的表达状况,结果如下：采用生物信息学的方法对已经在蛋白数据库中注册的由水稻基因组其中的Os02g0774300基因编码的mtHSP70进行系统分析,包括该蛋白的组成成分、拷贝、疏水性／亲水性、跨膜拓扑结构、信号肽、导肽、可溶性、蛋白质二级结构、基序及功能域分。结果表明该蛋白是非跨膜的可溶性蛋白,α螺旋和无规卷曲是其蛋白质二级结构的主要结构元件,β折叠零星散布于整个蛋白质中,包含多个基序位点和功能域,主要作为一种分子伴侣发挥作用,该蛋白在水稻线粒体中存在一个同源蛋白,序列一致性高达92%。mRNA被转录翻译后形成的初始蛋白一般要经过加工修饰才能成为有功能的蛋白质,因此蛋白在基因水平和蛋白水平的表达状况并不是完全一致的。本研究运用半定量RT-PCR和免疫印迹对其在盐胁迫诱导的水稻根尖细胞PCD过程中mtHSP70基因水平的表达情况进行分析。结果表明,该蛋白及其同源蛋白在盐胁迫诱导的PCD过程中mRNA和蛋白水平的表达量均上调。研究结果提示,mtHSP70可能通过影响呼吸链复合物的稳定性,进而调节线粒体内活性氧的产生。更多还原

【Abstract】 Salt stress-induced PCD in which mitochondria plays an important role in rice root tip cells was studied by using rice seedling Wuyunjing 8th in early period. In the previous study, it was indicated that 500 mmol/L NaCl could lead to PCD in root tip cells. Mitochondrial proteome was studied by two-dimensional gel electrophoresis in this sduty, the result showed that heat shock protein 70 (mtHSP70) was induced by the PCD and respiratory chain complex I decreased. Then, mtHSP70 was analyzed by bioinformatics. The results are as follows:The amino acid sequences of heat shock protein 70 from Oryza sativa (japonica cultivar-group), which were registered in Protein databases, were analyzed and predicted by the tools of informatics in the following aspects:the composition amino acid sequences, copies, hydrophobicity or hydrophilicity, trans-membrane topological structure, singnal peptides, target peptides, solubility, secondary structure, motifs and functional domains of protein, etc. The results were as follows:mtHSP70 was a hydrophilic, non-transmembrane and soluble protein; the main motifs of predicted secondary strcture of mtHSP70 were alpha helix and random coil, extended strand were spread to the whole secondary structure of protein; the amino acid sequences of mtHPS70 included many motifs and conserved functional domains; mtHSP70 often function as molecular chaperone; there is a homologous protein sequences of which up to 92% consistency and also located in the mitochondria.Generally, functional protein only be formated after the initial protein be modified. The expressions of mtHSP70 and its Homologous protein, were analysised by the tool of RT-PCR. The result shows that, their expressions on the gene level are all updated. The results suggest that, mtHSP70 may affect the tability of respiratory chain complex s, and regulate the generation of mitochondrial reactive oxygen species.更多还原