Molecular structure and regulatory potential of a T-DNA integration site in petunia.
The genomic structure surrounding a T-DNA integration site in a transgenic petunia plant, which shows deregulation of a root-specific promoter, was investigated. We have already demonstrated that T-DNA integration in this transformant (P13) had occurred close to a scaffold/matrix attachment region (S/MAR). A major question regarding the observed promoter leakiness was whether the T-DNA had integrated into the centre or at the border of the Petun-SAR and whether other regulatory elements are located within this genomic region. While small rearrangements were shown to occur during T-DNA integration in agreement with other reports, we find indications of the presence of a SINE retroposon--an apparent landmark for recombinogenic targets--at the integration site. Binding assays to both plant and animal nuclear scaffolds, supported by biomathematical analyses, reveal that the T-DNA is definitely located at the border of a strong S/MAR, which is in agreement with current models on the structure of integration sites. These results, together with a developmentally regulated leaf-specific enhancer effect of the Petun-SAR on gene expression in transgenic tobacco plants, indicate that the Petun-SAR demarcates the right border of a chromatin domain with genes predominantly active in leaves.
Dietz-Pfeilstetter
Antje
A
Federal Biological Research Centre for Agriculture and Forestry, Institute for Plant Virology, Microbiology and Biosafety, Messeweg 11/12, D-38104 Braunschweig, Germany. a.dietz@bba.de
Arndt
Nicola
N
Kay
Volker
V
Bode
Jürgen
J
D016960:Agrobacterium tumefaciens / Q000235:genetics; D001483:Base Sequence; D015139:Blotting, Southern; D002843:Chromatin / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D018744:DNA, Plant / Q000502:physiology*; D004277:DNA, Single-Stranded / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics; D036961:Matrix Attachment Region Binding Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D015530:Nuclear Matrix / Q000235:genetics*; D032306:Petunia / Q000235:genetics*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D014026:Nicotiana / Q000235:genetics; D014170:Transformation, Genetic
D002843:Chromatin; D004269:DNA, Bacterial; D018744:DNA, Plant; D004277:DNA, Single-Stranded; D036961:Matrix Attachment Region Binding Proteins; C036483:T-DNA; D005966:Glucuronidase