title: Regulation of transcription through light-activation and light-deactivation of triplex-forming oligonucleotides in mammalian cells.
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.
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, 27695, United States.
authors.forename: Jeane M
authors.initials: JM
authors.lastname: Govan
authors.forename: Rajendra
authors.initials: R
authors.lastname: Uprety
authors.forename: James
authors.initials: J
authors.lastname: Hemphill
authors.forename: Mark O
authors.initials: MO
authors.lastname: Lively
authors.forename: Alexander
authors.initials: A
authors.lastname: Deiters
mesh_terms: D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism*; D010775:Photic Stimulation / Q000379:methods; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D009841:Oligonucleotides; C051802:triplex DNA; D004247:DNA