Regulation of transcription through light-activation and light-deactivation of triplex-forming oligonucleotides in mammalian cells

ACS Chem Biol. 2012 Jul 20;7(7):1247-56. doi: 10.1021/cb300161r. Epub 2012 May 11.

Abstract

Triplex-forming oligonucleotides (TFOs) are efficient tools to regulate gene expression through the inhibition of transcription. Here, nucleobase-caging technology was applied to the temporal regulation of transcription through light-activated TFOs. Through site-specific incorporation of caged thymidine nucleotides, the TFO:DNA triplex formation is blocked, rendering the TFO inactive. However, after a brief UV irradiation, the caging groups are removed, activating the TFO and leading to the inhibition of transcription. Furthermore, the synthesis and site-specific incorporation of caged deoxycytidine nucleotides within TFO inhibitor sequences was developed, allowing for the light-deactivation of TFO function and thus photochemical activation of gene expression. After UV-induced removal of the caging groups, the TFO forms a DNA dumbbell structure, rendering it inactive, releasing it from the DNA, and activating transcription. These are the first examples of light-regulated TFOs and their application in the photochemical activation and deactivation of gene expression. In addition, hairpin loop structures were found to significantly increase the efficacy of phosphodiester DNA-based TFOs in tissue culture.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • DNA / chemistry
  • DNA / metabolism*
  • HEK293 Cells
  • Humans
  • Nucleic Acid Conformation*
  • Oligonucleotides / chemistry
  • Oligonucleotides / metabolism*
  • Photic Stimulation* / methods
  • Transcription, Genetic / physiology*

Substances

  • Oligonucleotides
  • triplex DNA
  • DNA