In vivo photoreaction of a chiral cobalt complex: DNA cleavage by Co(DIP)3(3+) in mammalian cells

Mono- and dicarboxylic polypyridyl-Ru complexes as potential cell DNA dyes and transfection agents

A ruthenium coordination complex, incorporating two highly extended pi-systems DIP and two carboxylic groups: [Ru(DIP)2(L-L)]2+ where DIP=4,7-diphenyl-1,10-phenanthroline and L-L=4,4'-dicarboxy-2,2'-bipyridine, is found to be of biological interest. It constitutes an effective nuclear DNA dye for living cells: fluorescent, permeant, biocompatible, high Stokes shift. These features are commented in terms of hydrophobicity and DNA binding. In addition, this complex is shown to internalize a plasmid carrying the enhanced green fluorescent protein (EGFP) gene. Positive results are obtained for gene expression, which is related to condensation of the DNA by this ruthenium agent. This opens up an innovative transfection route based on metal complexes.

Chemical and photochemical probing of DNA complexes

An overview of the chemical and photochemical probes which over the past ten years have been used in studies of DNA/ligand complexes and of non-B-form DNA conformations is presented with emphasis on the chemical reactions of the probes with DNA and on their present 'use-profile'. The chemical probes include: dimethyl sulfate, ethyl nitroso urea, diethyl pyrocarbonate, osmium tetroxide, permanganate, aldehydes, methidiumpropyl-EDTA-Fell (MPE), phenanthroline metal complexes and EDTA/FeII. The photochemical probes that have been used include: psoralens, UVB, acridines and uranyl salts. The biological systems analysed by use of these probes are reviewed by tabulation.