A 1-kb Bacteriophage Lambda Fragment Functions as an Insulator to Effectively Block Enhancer–Promoter Interactions in Arabidopsis thaliana


DOI: 10.1007/s11105-009-0122-3

Cite this article as:
Singer, S.D., Hily, JM. & Liu, Z. Plant Mol Biol Rep (2010) 28: 69. doi:10.1007/s11105-009-0122-3


Enhancers are known to be capable of overriding the specificity of nearby promoters in a distance-dependent manner, which is problematic when multiple promoters coexist in a single transgene unit. In an attempt to determine whether enhancer activation function is inversely related to its distance from the target promoter, we inserted 1-, 2-, and 4-kb bacteriophage λ fragments, respectively, between the cauliflower mosaic virus 35S enhancer and a flower-specific AGAMOUS second intron-derived promoter (AGIP) fused to the β-glucuronidase (GUS) coding region. In the absence of an insert sequence, the 35S enhancer activates AGIP-driven GUS expression in vegetative tissues of transgenic Arabidopsis thaliana lines. Moreover, neither the 2-kb nor the 4-kb λ fragment was able to block GUS expression in transgenic leaves, implying that the 35S enhancer can override a distance barrier of at least 4 kb in our system. Unexpectedly, insertion of the 1-kb λ insert into the same site resulted in diminished GUS expression in transgenic leaves. Our data indicate that this fragment functions as a true enhancer-blocking insulator that could potentially be utilized to minimize enhancer–promoter interference between multiple transcriptional units within a plasmid vector during plant transformation experiments.


Arabidopsis thaliana Bacteriophage lambda Cauliflower mosaic virus 35S promoter Enhancer-blocking insulator Enhancer–promoter interaction 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Stacy D. Singer
    • 1
    • 2
  • Jean-Michel Hily
    • 1
    • 2
  • Zongrang Liu
    • 1
  1. 1.USDA-ARS Appalachian Fruit Research StationKearneysvilleUSA
  2. 2.Department of Plant Pathology, New York State Agricultural Experiment StationCornell UniversityGenevaUSA

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