Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Plant J. 2017 Nov;92(3):481-494. doi: 10.1111/tpj.13671. Epub 2017 Oct 6.
Tapetum-specific promoters have been successfully used for developing transgenic-based pollination control systems. Although several tapetum-specific promoters have been identified, in-depth studies on regulation of such promoters are scarce. The present study analyzes the regulation of the A9 promoter, one of the first tapetum-specific promoter identified in Arabidopsis thaliana. Transcription factors (TFs) AtMYB80, AtMYB1 (positive regulators) identified by in silico analysis were found to upregulate A9 promoter activity following the over-expression of the TFs in transient and stable (transgenic) expression assays in both A. thaliana and tobacco. Furthermore, mutations of binding sites of these TFs in the A9 promoter led to loss of its activity. The role of a negative regulator AtMYB4 was also studied by analyzing the activity of A9 promoter following transient expression of RNAi against the TF and by mutating binding sites for AtMYB4 in the A9 promoter. While no changes were observed in case of A. thaliana, the A9 promoter was activated in the roots of transgenic tobacco plants, highlighting the role of these cis-elements in keeping the A9 promoter repressed in the roots of tobacco.
已成功使用花药特异性启动子开发基于转基因的授粉控制系统。尽管已经鉴定出几种花药特异性启动子，但对这些启动子的调控的深入研究却很少。本研究分析了 A9 启动子的调控，A9 启动子是在拟南芥中鉴定出的第一个花药特异性启动子之一。通过计算机分析鉴定出的转录因子（TFs）AtMYB80、AtMYB1（正调控因子）在拟南芥和烟草的瞬时和稳定（转基因）表达试验中，过表达 TFs 后发现能上调 A9 启动子活性。此外，A9 启动子中这些 TF 的结合位点发生突变会导致其活性丧失。通过分析针对该 TF 的 RNAi 瞬时表达后 A9 启动子的活性以及在 A9 启动子中突变 AtMYB4 的结合位点，也研究了负调控因子 AtMYB4 的作用。虽然在拟南芥中没有观察到变化，但 A9 启动子在转基因烟草植物的根中被激活，这突出了这些顺式元件在抑制烟草根中 A9 启动子的作用。
