A/T-rich sequences act as quantitative enhancers of gene expression in transgenic tobacco and potato plants.
The role of an A/T-rich positive regulatory region (P268, -444 to -177 from the translation start site) of the pea plastocyanin gene (PetE) promoter has been investigated in transgenic plants containing chimeric promoters fused to the beta-glucuronidase (GUS) reporter gene. This region enhanced GUS expression in leaves of transgenic tobacco plants when fused in either orientation to a minimal pea PetE promoter (-176 to +4) and in roots when fused in either orientation upstream or downstream of a minimal cauliflower mosaic virus 35S promoter (-90 to +5). The region was also able to enhance GUS expression in microtubers of transgenic potato plants when placed in either orientation upstream of a minimal class I patatin promoter (-332 to +14). Dissection of P268 revealed that cis elements responsible for enhancing GUS expression from the minimal PetE promoter were distributed throughout P268. Multiple copies of a 31 bp A/T-rich sequence from within P268 and of a 26 bp random A/T sequence were able to enhance GUS expression from the minimal PetE promoter, indicating that A/T-rich sequences are able to act as quantitative, non-tissue-specific enhancer elements in higher plants.
Sandhu
J S
JS
Department of Plant Sciences and Cambridge Centre for Molecular Recognition, University of Cambridge, UK.
Webster
C I
CI
Gray
J C
JC
D001483:Base Sequence; D001665:Binding Sites; D002265:Carboxylic Ester Hydrolases; D017796:Caulimovirus / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D005966:Glucuronidase / Q000235:genetics; D025741:HMGA1a Protein; D006609:High Mobility Group Proteins / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D018532:Pisum sativum / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D010970:Plastocyanin / Q000235:genetics*; D011198:Solanum tuberosum / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*
D018744:DNA, Plant; C107092:HMGA1a Protein, plant; D006609:High Mobility Group Proteins; D009838:Oligodeoxyribonucleotides; D010940:Plant Proteins; C043222:patatin protein, Solanum tuberosum; D025741:HMGA1a Protein; D010970:Plastocyanin; D002265:Carboxylic Ester Hydrolases; D005966:Glucuronidase