香蕉果实成熟相关基因ACO1启动子区的克隆及其功能初探

根据已报道的香蕉课实表达ACC氧化酶基因（ACO1）的序列，用改进的接头连接PCR法从香蕉基因组中扩增并克隆了此基因5′旁侧区1526bp的片段，其中包含一个推测的TATA盒序列；与已公布的两个香蕉ACC氧化酶基因启动子序列（分别为934bp和1451bp）的相似性各为97．3％（Lopez-Gomez等）和88．8％（May和Kipp)。将4个含有不同大小启动子区的克隆片段与GUS基因编码区连接构建成嵌合成基因，通过基因枪轰击转入香蕉叶、根和果实的细胞后，瞬时表达结果表明不同大小的ACO1启动子区段都只在果实细胞中指导GUS基因表达，证明该启动子具有指导基因在果实中表达的功能，并推测负责果实特异性的顺式元件可能位于启动子近端0．7kb区段之内，在468至822的355bp区段内可能在与正控制有关的顺式元件。

Cloning of Promoter of Banana Fruit Ripening-related ACO1 and Primary Study on Its Function

According to the published sequence of ACC oxidase gene(ACO1) which was shown to express in banana fruits, we cloned its 5'-flanking region by improved adaptor ligation PCR. The 1526 bp fragment contained a putative TATA-box. Sequence alignment of our promoter with two published (934 bp and 1451 bp) revealed 97.3% (López-Gómez et al.) and 88.8% (May and Kipp) similarity in nucleotide sequence, respectively. The 5'-flanking fragments in different length were fused to the coding sequence of GUS gene. These constructs were delivered to leaf, root and fruit cells of banana via particle bombardment. The results of transient gene expression assay showed that the cloned ACO1 promoter was able to direct fruit-specific gene expression, and that the regulatory region for fruit-specificity was probably located in the 0.7 kb 5'-flanking sequence of the gene and some positive regulatory elements may exist within the region of 355 bp from 468 to 822.