Jones J D, Dunsmuir P, Bedbrook J
Advanced Genetic Sciences, Inc., 6701 San Pablo Ave., Oakland, CA 94608, USA.
EMBO J. 1985 Oct;4(10):2411-8. doi: 10.1002/j.1460-2075.1985.tb03949.x.
Promoter DNA sequences from a petunia chlorophyll a/b binding protein gene were fused to octopine synthase DNA sequences and the resulting chimaeric genes were introduced into petunia and tobacco cells. Populations of transformed regenerated petunia plants containing the chimaeric genes were examined so that the expression of any particular construction could be compared between independent transformants. Substantial variation was observed between transformants in the level of chimaeric gene expression. In general, transcriptional fusions in which a linker sequence interrupted the 5'-untranslated region gave rise to less chimaeric mRNA accumulation than a translational fusion. In the most actively expressing transformants the amount of mRNA from the introduced chimaeric genes was half that of the endogenous wild-type gene. Transcription initiated at the same place in the chimaeric and endogenous genes. Construction of the translational cab/ocs fusion caused three amino acid changes in the octopine synthase protein and functional octopine synthase enzyme was absent from plants in which mRNA for the chimaeric gene was abundantly expressed.
将矮牵牛叶绿素a/b结合蛋白基因的启动子DNA序列与章鱼碱合成酶DNA序列融合，然后将所得的嵌合基因导入矮牵牛和烟草细胞。对含有嵌合基因的转化再生矮牵牛植株群体进行检测，以便在独立转化体之间比较任何特定构建体的表达情况。在嵌合基因表达水平上，转化体之间观察到了显著差异。一般来说，与翻译融合相比，其中接头序列中断5'-非翻译区的转录融合产生的嵌合mRNA积累较少。在表达最活跃的转化体中，导入的嵌合基因产生的mRNA量是内源性野生型基因的一半。转录在嵌合基因和内源性基因的同一位置起始。翻译型cab/ocs融合的构建导致章鱼碱合成酶蛋白发生三个氨基酸变化，在大量表达嵌合基因mRNA的植株中不存在功能性章鱼碱合成酶。
