Promoter regions of the extA extensin gene from Brassica napus control activation in response to wounding and tensile stress.
Promoter regions of the extA extensin gene from Brassica napus control activation in response to wounding and tensile stress.
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DOI：
10.1023/a:1005918816630
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发表时间：
1998-07-01
影响因子：
5.1
通讯作者：
Shirsat, AH
中科院分区：
文献类型：
--
作者：
Elliott, KA;Shirsat, AH
为了鉴定甘蓝型油菜extA延伸蛋白基因中的控制顺式作用启动子区域，分析了与uidA（B-葡萄糖醛酸酶）报道编码序列连接的5'-159、-433、-664、-789和-940bp启动子截短在转基因烟草中的表达。 -159 和-433 bp 截短导致植物内所有细胞类型的非特异性表达。在所有细胞类型中表达水平增加 10 倍的激活区位于 -159 至 -433 bp 之间。在-664 至-789 bp 之间发现了阻遏区域；去除该区域导致表达量增加 15 倍。组织化学分析表明，含有-664、-789和-940 bp截短的转基因仅在韧皮部引导融合基因的表达。位于-433 至-664 bp 之间的负调控区抑制非韧皮部细胞类型中的表达。在植物受到拉应力的区域，负调控区施加的抑制被克服，从而允许在所有细胞类型中表达。控制所有细胞类型中绝对表达水平的定量阻遏物和激活物区域与控制响应拉应力的细胞类型特异性表达的负调节区域分开。发现伤口反应区域位于-940 至-3500 bp 之间。因此，extA 基因处于复杂的控制之下，受到 4 组正作用和负作用顺式区域的调节，这些区域控制伤口诱导性、响应拉应力的激活以及定量表达水平。
To identify controlling cis acting promoter regions in the B. napus extA extensin gene, expression in transgenic tobacco of 5' -159, -433, -664, -789 and -940 bp promoter truncations linked to the uidA (B-glucuronidase) reporter coding sequence were analysed. The -159 and -433 bp truncations directed non specific expression in all cell types within the plant. An activator region which increased expression levels 10 fold in all cell types was located between -159 to -433 bp. A repressor region was found between -664 to -789 bp; removal of this region resulted in a 15 fold increase in expression. Histochemical analysis showed that transgenics containing the -664, -789 and -940 bp truncations directed expression of the fusion gene only in the phloem. A negative regulatory region located between -433 to -664 bp repressed expression in non-phloem cell types. In areas of the plant subject to tensile stress, the repression exerted by the negative regulatory region was overcome, allowing expression in all cell types. The quantitative repressor and activator regions which controlled absolute expression levels in all cell types were seperate from the negative regulatory region which controlled cell type specific expression in response to tensile stress. A wound responsive region was found to be located between -940 to -3500 bp. Thus, the extA gene is under complex control, being regulated by 4 sets of positively and negatively acting cis regions, which control wound inducibility, activation in response to tensile stress, and quantitative expression levels.