Interaction between composite elements in the napA promoter: both the B-box ABA-responsive complex and the RY/G complex are necessary for seed-specific expression.

摘要: During seed maturation, the transcriptional activity of napin genes is regulated by developmental signals involving activator ABI3 and abscisic acid (ABA). To localize cis elements involved in seed-specific napA promoter, a systematic analysis was performed focusing on two major element complexes, B-box RY/G. Substitution mutation using promoter-reporter gene fusions stable transgenic tobacco showed synergistic interactions between within these complexes. The distal part shows similarities to response proximal portion contains CA-rich element. In vitro studies Exonuclease III protection electrophoretic mobility shift assays revealed binding nuclear proteins B-box. parts were found bind distinct protein By gain-of-function with tetramer fused truncated (−46) cauliflower mosaic virus (CaMV) 35S minimal it demonstrated that mediates strong seeds. Further, shown constitute an ABA-responsive complex, since ABA-responsiveness vegetative tissues construct containing CaMV enhancer (−343 −90). Thus, promoter relies combinatorial interaction RY/G complex during ABA development.