Psoralen conjugates for visualization of genomic interstrand cross-links localized by laser photoactivation.

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Thazhathveetil AK, Liu ST, Indig FE, Seidman MM

Psoralen conjugates for visualization of genomic interstrand cross-links localized by laser photoactivation.

Bioconjug Chem. 2007 Mar-Apr;18(2):431-7.

PubMed ID

17373769 [ View in PubMed

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Abstract

DNA interstrand cross-links are formed by chemotherapy drugs as well as by products of normal oxidative metabolism. Despite their importance, the pathways of cross-link metabolism are poorly understood. Laser confocal microscopy has become a powerful tool for studying the repair of DNA lesions that can be detected by immunofluorescent reagents. In order to apply this approach to cross-link repair, we have synthesized conjugates of 4,5',8-trimethylpsoralen (TMP) and easily detected compounds such as Lissamine rhodamine B sulfonyl chloride (LRB-SC), biotin, and digoxigenin. These conjugates are activated by UVA, and we have analyzed the intracellular localization of DNA damage and DNA reactivity by confocal and immunofluorescence microscopy. The LRB-SC-TMP conjugate 2 appeared mainly in the mitochondria, while the biotin-TMP conjugate 4 preferentially localized in the cytoplasm. Adducts formed by UVA and digoxigenin conjugates of TMP 7a and 4,5'-dimethylangelicin (DMA) 7b, which forms only monoadducts, were largely localized to the nucleus. Exposure of cells incubated with 7a and 7b to a 364 nm UV laser directed toward defined nuclear regions of interest resulted in localized adduct formation which could be visualized by immunofluorescence. Repair-proficient cells were able to remove the photoadducts, while repair-deficient cells were unable to repair the damage. The results indicated that the digoxigenin-TMP conjugate 7a and digoxigenin-DMA conjugate 7b can be used for studying the repair of laser localized DNA monoadducts and cross-links.

DrugBank Data that Cites this Article

Drugs

Trioxsalen

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Trioxsalen	DNA	Nucleotide	Humans	Yes	Cross-linking/alkylation	Details