油菜质膜水孔蛋白BnPIP1基因启动子区的克隆及初步的功能分析

利用双链接头介导PCR的染色体步行技术, 克隆了油菜质膜水孔蛋白BnPIP1基因上游1.6 kb的调控区域(GenBank登录号为AF472487). 序列分析表明, 该片段中含有种子萌发特异性序列及维管束特异性序列. 将其全长片段及5′端不同长度的缺失片段与gus(uidA)基因连接构建植物表达载体, 转化烟草. GUS组织化学染色表明, 全长1.6 kb片段具有较强的启动子活性. GUS染色主要分布在细胞迅速增生的部位及维管束组织中. 启动子缺失试验的GUS染色结果表明, -1610~-1030 bp区段的缺失使gus基因的表达明显变弱, 推测该区段含有启动子的正调控元件; -1030~-902 bp可能存在强烈抑制基因表达的负调控元件; -902~-19 bp的片段亦可驱动gus基因的高水平表达.     

Cloning of the promoter region of plasma membrane aquaporin BnPIP1 from Brassica napus and its functional analysis

Aquaporins make water-selective channels in plants, facilitating the permeation of water through membranes and adjusting water fast transport during seed germination, cell elongation, stoma movement, fertilization and responses to environmental stresses. They belong to the MIP (major intrinsic protein) family with molecular weight of 2629 kD and are characterized by six membrane-spanning a-helixes connected by five loops and short N-terminal and C-terminal domains in the cytoplasm[13]. The p…     

Cloning of the promoter region of plasma membrane aquaporin<Emphasis Type="Italic">BnPIP1</Emphasis> from<Emphasis Type="Italic">Brassica napus</Emphasis> and its functional analysis

A 1.6 kb upstream regulatory sequence (GenBank accession no. AF472487) of plasma membrane aquaporinBnPIP1 gene fromBrassica napus was obtained by genomic walking based on ligation-mediated PCR method. Sequence analysis indicated that this fragment contained seed germination specific and vascular specific sequences. The 1.6 kb upstream sequence and various 5′ end deleted sequences were fused withuidA gene and constructed into plant expression vectors which were used for tobacco transformation. GUS histochemical assay showed that the 1.6 kb fragment had high levels of promoter activity and the GUS staining was mainly distributed in vascular systems and tissues with rapid expanding and proliferating cells. Promoter deletion analysis showed that the deletion of -1610 — -1030 bp resulted in a dramatic reduction in GUS activity. It was assumed that there might be cis-acting element(s) existing in this region. Whereas, the region located at -1030 — -902 bp strongly inhibited the expression ofgus and probably contained negative regulatory element(s). The fragment of -902 — -19 bp could also directgus expression at high level.