ARS | Publication request: A 1-kb bacteriophage lambda fragment functions as an insulator to effectively block enhancer-promoter interactions in Arabidopsis thaliana

Submitted to: Plant Molecular Biology Reporter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2009
Publication Date: August 8, 2009
Repository URL: http://www.springerlink.com/content/8123502324g44g75/fulltext.html
Citation: Singer, S.D., Hily, J., Liu, Z. 2009. A 1-kb bacteriophage lambda fragment functions as an insulator to effectively block enhancer-promoter interactions in Arabidopsis thaliana. Plant Molecular Biology Reporter. 28:69-76.

Interpretive Summary: Promoters that drive gene expression are essential for the genetic improvement of crops via biotechnological approach. However, in many cases, multiple promoters employed in a single transformation vector have been found to interact or interfere with each other, leading to undesired or altered gene expression. To address this problem, we have performed molecular analyses to identify insulators and have found that a DNA fragment from the genome of a bacterial virus can function as an insulator in plants. This insulator is able to prevent the promoter interaction in plants. The identified insulator has potential utilization for the improvement of future transformations and crop improvement technologies.

Technical Abstract: The 35S cauliflower mosaic virus (CaMV) promoter contains an enhancer element that is able to override the tissue-, organ- and developmental-stage specificity of nearby promoters. Consequently, the precise control of transgene expression in transgenic plants, which often contain the 35S CaMV promoter used to drive the selectable marker gene, has been problematic. We have found that a 1 kb bacteriophage lambda fragment is able to effectively block such interference in Arabidopsis thaliana without inhibiting the performance of either enhancer or promoter with elements from which they were not insulated. These results suggest that the lambda sequence acts as an enhancer-blocking insulator in Arabidopsis, and its function depends on its position between the enhancer and target promoter.