期刊
MOLECULAR AND GENERAL GENETICS
卷 264, 期 6, 页码 860-870出版社
SPRINGER-VERLAG
DOI: 10.1007/s004380000376
关键词
dexamethasone; tetracycline; cytokinin; synthetic promoters; chemically inducible gene expression
The chimeric transcriptional activator TGV mediates dexamethasone (dx)-inducible and tetracycline (tc)-repressible transgene expression in tobacco (dx-on/ tc-off system). The expression profiles of four different synthetic target promoters, comprising multiple TGV binding sites upstream of a core promoter, were characterised using the sensitive luciferase assay. Induction factors of over 1000 were measured in roots and leaves of over 30% of the transgenic plants, irrespective of the promoter used. Promoters P-TF and P-Tax, which carry the -48 to +1 region of the Cauliflower Mosaic Virus 35S promoter, showed higher expression levels in both the uninduced and induced states than P-Top10 and P-TFM, which harbour several point mutations in this region. Moreover, P-Tax expressed higher background activities than P-TF, indicating that the sequence of the synthetic regulatory region can influence background levels. The usefulness of the dx-on/tc-off system for experiments addressing gene function was demonstrated by using it to control the expression of isopentenyl transferase. This enzyme catalyses the rate-limiting step in cytokinin biosynthesis and causes phenotypic effects even at low expression levels. Only dr-induced transgenic plants displayed phenotypic alterations indicative for increased cytokinin synthesis (e.g. outgrowth of lateral buds). Simultaneous treatment of selected buds with the anti-inducer tc suppressed bud growth. This result suggests that cytokinins cannot serve as mobile signals to elicit the release of apical dominance in tissues compromised for enhanced cytokinin synthesis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据