植物转基因整合座位的结构

通过农杆菌和直接DNA转移技术所获得的转基因植株都具有复杂的转基因座位, 转基因整合染色体和染色体区段是随机的, 但组织培养的选择作用表现为非随机性, 偏向整合于染色体的基因富集区。转基因座位除少数含有完整的单拷贝转基因之外, 大多数转基因座位中外源转基因片段、基因组片段和填充DNA相间而存在。转基因座位中转基因及基因组DNA片段产生缺失、重复和染色体的重排, 转基因的完整性对转基因表达具有重要作用。

Structures of transgenic integration loci in transformed plants

The plants transformed by either Agrobacterium-mediated or directly delivered DNA transformation possess complex transgenic loci.The transgenes tend to be integrated into gene-rich regions on chromosomes due to selection of transgenic cells during tissue culture rather than integrated elsewhere randomly.Fragments of transferred DNA are inter-spersed with genomic DNA and filler DNA at most of transgenic loci except a few which contain complete single-copy of transgene.Analysis of transgenic loci flanking sequences indicated that deletion,duplication and chromosomal rearrange-ment often occurred for transgene and genomic DNA.The complete transgenic structure is important for its expression in transformed plants.