Targeting of the synthesized polypeptide in the cells is an important research field in modern cell biology. Cowpea trypsin inhibitor (cpti) gene has been modified and a fusion protein gene (sck) was produced by fusing a signal peptide sequence at cpti 5' end and an endoplasm reticulum (ER) retention signal peptide at cpti3' end respectively. The signal peptide can direct the newly synthesized polypeptide into ER, while ER retention signal can make the protein retained in the ER and its derivative protein body. ELISA test indicated that the accumulation level of foreign CpTI protein in sck transgenic tobacco (Nicotiana tabacum L.) was two times higher than cpti transgenic tobaccos and some individuals were four times higher. At the same time, sck transgenic tobacco has a high resistance to Lepidoptera pest due to the increased accumulation level of foreign CpTI protein. The strategy of foreign protein targeting can be used to increase the accumulation level of foreign protein in transgenic plants and can be widely applied to other related research field in plant genetic engineering.
多糖污染是从田间水稻叶片和未成熟种子等高含糖组织中提取高质量RNA的主要限制因素。我们介绍一种简单经济的RNA提取方法,它适合从水稻叶片和未成熟种子这些富含多糖的组织中提取总RNA。这种方法可以克服产率低和质量低的问题。RNA提取后经过电泳和分光光度计分析结果表明,每克水稻组织总RNA产率在520μg到800μg之间,OD260/230比值大于2.0,OD260/280比值大于1.9。提取的RNA可以用于体外反转录cDNA、mRNA分离和基因表达系列分析(serial analysis of gene expression,SAGE)库的构建。
