Localization of light-inducible and tissue-specific regions of the spinach ribulose bisphosphate carboxylase/oxygenase (rubisco) activase promoter in transgenic tobacco plants.
Deletions in the spinach rubisco activase (Rca) promoter in transgenic tobacco were analyzed to define the regions necessary for conferring light-inducible and tissue-specific expression. Transgenic plants were constructed with Bal 31 deletions of the Rca promoter fused to the coding region of the bacterial reporter gene beta-glucuronidase (GUS). Analysis of the Rca deletion mutants localized the region conferring normal expression downstream from -294 relative to the Rca transcription start site. A second set of transgenic plants containing the cauliflower mosaic virus (CaMV) 35S enhancer fused to the 3' end of the Rca/GUS constructs demonstrated the presence of a light-responsive element between -150 and -78 active in leaves. Regions 10 bp long within the light-responsive region, which included putative G box and GT elements, were removed by recombinant polymerase chain reaction. Deletion of the G box element resulted in a loss of gene expression in the leaves of transgenic tobacco, while deletion of the GT motif caused a 10-100-fold increase in expression in roots. However, site-directed mutagenesis of the GT motif resulted in expression patterns identical to the normal promoter. These experiments demonstrated that light-inducible and tissue-specific expression of the Rca promoter involves multiple cis elements proximal to the transcription start site, and that interactions between these elements are essential for regulating expression.
Orozco
B M
BM
Department of Plant Biology, University of Illinois at Urbana-Champaign.
Ogren
W L
WL
D005786:Gene Expression Regulation; D017343:Genes, Plant; D008027:Light; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics* / Q000378:metabolism; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D014026:Nicotiana / Q000235:genetics; D014158:Transcription, Genetic; D014675:Vegetables / Q000235:genetics*
D010940:Plant Proteins; D012333:RNA, Messenger; C054765:rca protein, plant; D012273:Ribulose-Bisphosphate Carboxylase