不同调控序列作用下GUS基因在烟草中瞬时表达活性的研究

以pBI121为出发质粒, 利用烟草泛素启动子Ubi.U4、CaMV35S启动子以及Kozak序列构建4种GUS基因表达载体,通过叶盘转化法转化烟草叶片, 检测瞬时表达活性, 研究不同调控序列对外源基因表达的调控作用。结果表明: CaMV35S启动子附加Kozak序列后使GUS活性比独立使用CaMV35S提高了近2倍; 双CaMV35S启动子附加Kozak序列驱动GUS基因的表达活性与单CaMV35S附加Kozak序列相当; 烟草泛素启动子附加Kozak序列的表达活性为CaMV35S启动子附加Kozak序列的1.5倍; Ubi.U4-CaMV35S复合启动子附加Kozak序列驱动GUS基因表达水平最高, 其表达效率是双CaMV35S启动子附加Kozak序列调控下GUS表达效率的3倍, 为CaMV35S独立作用时的10倍。

Transient Expression of GUS Gene Controlled by Different Regulator Sequences of Tobacco

GUS gene controlled by different regulator sequences (CaMV35S promoter, Ubi.U4 promoter and Kozak sequence) were introduced into the leaves of tobacco. Transient expression assay revealed a 2-fold increase in GUS activity in leaves with GUS expression driven by the CaMV35S promoter fused to the Kozak sequence (pSKG) as compared with the pBI121. The expression of GUS driven by a double CaMV35S promoter with the Kozak sequence was not significantly different from that driven by the single CaMV35S promoter with the Kozak sequence. Expression with the Ubi.U4 promoter with the Kozak sequence of pUKG yielded about a 1.5-fold higher level of GUS activity than expression with the CaMV35S promoter with the Kozak sequence. The tandem Ubi.U4-CaMV35S promoter with the Kozak sequence was the most effective among the regulator sequences and gave a 3-fold higher expression level than that driven by the double CaMV35S promoter with the Kozak sequence and a 10-fold higher expression level than that driven by the single CaMV35S promoter.