Localization of light-inducible and tissue-specific regions of the spinach ribulose bisphosphate carboxylase/oxygenase (rubisco) activase promoter in transgenic tobacco plants
✍ Scribed by Beverly M. Orozco; William L. Ogren
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 956 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0167-4412
No coin nor oath required. For personal study only.
✦ Synopsis
Deletions in the spinach rubisco activase (Rca) promoter in transgenic tobacco were analyzed to define the regions necessary for conferring fight-inducible and fissue-specifc expression. Transgenic plants were constructed with Bal 31 deletions of the Rca promoter fused to the coding region of the bacterial reporter gene fl-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 fight-responsive region, which included putative G box and GT elements, were removed by recombinant polymerase chain reaction. Deletion of the G box element resuited 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.