一段烟草核基质结合区的分离及对转基因表达的效果

Effect of Nuclear Matrix Attachment Region on Transgene Expression In Transgenic Tobacco

采用PCR方法,从烟草基因组中分离了一段核基质结合区(matrix attachment region,MAR),将其构建到β-葡糖醛酸酶(β-glucuronidase,GUS)基因(uidA)的两侧翼,形成MARs调控的植物表达载体,将此表达载体与不含MARs序列的植物表达载体通过农杆菌转化烟草。对转基因植株进行GUS活性定量测定,结果表明,MAR可以提高外源uidA基因的表达水平,与不含MAR的转化植株相比,外源基因的平均表达水平提高了1.5倍,最高达6倍,但MAR的引入不能降低转基因植株个体间表达水平的差异。

Matrix attachment regions （MARs） are sequences in the DNA of eukaryotic chromosomes where the nuclear matrix attaches. A MAR fragment was cloned from tobacco （Nicotiana tabacum L. ） by PCR method. This sequence was used to flank the β-glucuronidase （GUS） report gene within the T - DNA of the binary vector. Vectors containing or lacking MARs were then used to transform tobacco plants by Agrobacterium tumfaciens. Transgenic plants containing the MAR sequences flanking the GUS gene exhibited higher levels of transgene expression compared with transgenic plants which lacked the MAR. On average, plants transformed with MAR-containing vector expressed GUS at level 1.5 - fold higher than controls. However, the expression differences among individual transformants were still obvious.