Friedrich Miescher Institut, PO Box 2543, CH-4002 Basel, Switzerland.
EMBO J. 1988 Dec 20;7(13):4021-6. doi: 10.1002/j.1460-2075.1988.tb03295.x.
Although the generation of transgenic plants is now routine, the integration of foreign genetic information has so far been at random sites in the genome. We now present evidence for directed integration into a predicted location in the host plant genome. Protoplasts of transgenic tobacco (Nicotiana tabaccum) plants carrying copies of a partial, non-functional drug-resistance gene in the nuclear DNA were used as recipients for DNA molecules containing the missing part of the gene. Molecular and genetic data confirm the integration of the foreign DNA through homologous recombination within overlapping parts of the protein coding region, resulting in the formation of an active gene in the host chromosome. This approach is referred to as gene targeting. The gene targeting frequency (the number of drug-resistant clones resulting from gene correction compared to the number of resistant clones from parallel experiments with a similar non-interrupted hybrid gene) was 0.5-4.2x10. These experiments demonstrate the possibility of producing transgenic plants with desired modifications to a specific nuclear gene.
尽管现在已经可以常规地生成转基因植物，但外源遗传信息的整合迄今为止都是随机发生在基因组的某个位置上。我们现在提供了证据，证明外源遗传信息可以定向整合到宿主植物基因组的一个预测位置上。携带核 DNA 中部分非功能药物抗性基因的转基因烟草（Nicotiana tabaccum）原生质体被用作含有缺失部分基因的 DNA 分子的受体。分子和遗传数据证实，通过同源重组整合了蛋白编码区重叠部分的外源 DNA，导致宿主染色体中形成一个活性基因。这种方法被称为基因靶向。基因靶向频率（通过基因校正产生的抗药性克隆数与使用类似未中断杂种基因的平行实验产生的抗药性克隆数之比）为 0.5-4.2x10。这些实验证明了对特定核基因进行所需修饰的产生转基因植物的可能性。
