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Elucidating the human transcriptional regulatory network is a challenge of the post-genomic era. Technical progress so far is impressive, including detailed understanding of regulatory mechanisms for at least a few genes in multicellular organisms, rapid and precise localization of regulatory regions within extensive regions of DNA by means of cross-species(More)
Chemical agents able to interfere with DNA topoisomerases are widespread in nature, and some of them have outstanding therapeutic efficacy in human cancer and infectious diseases. DNA topoisomerases are essential enzymes that govern DNA topology during fundamental nuclear metabolic processes. Topoisomerase-interfering compounds can be divided into two(More)
The cytotoxic activity of mitoxantrone and related anthracenediones has been ascribed to the ability of these compounds to interfere with DNA topoisomerase II function, resulting in DNA cleavage stimulation. The molecular details of enzyme inhibition by these intercalating agents remain to be defined. In an attempt to identify the structural determinants(More)
Clerocidin, a diterpenoid with antibacterial and antitumor activity, stimulates in vitro DNA cleavage mediated by mammalian and bacterial topoisomerase (topo) II. Different from the classical topoisomerase poisons, clerocidin-stimulated breaks at guanines immediately preceding the sites of DNA cleavage are not resealed upon heat or salt treatment. To(More)
The effects of mono- and divalent metal ions on the DNA gyrase B subunit, on its 43 kDa and 47 kDa domains, and on two mutants in the Toprim domain (D498A and D500C) were investigated by means of circular dichroism and protein melting experiments. Both types of metal ion, with the notable exception of Mn2+, did not affect the conformational properties of(More)
DNA Topoisomerase II (Top2) is an essential nuclear enzyme that regulates the topological state of the DNA, and a target of very effective anticancer drugs including anthracycline antibiotics. Even though several aspects of drug activity against Top2 are understood, the drug receptor site is not yet known. Several Top2 mutants have altered drug sensitivity(More)
Antitumor agents targeting DNA and DNA-associated processes are widely used in the treatment of human cancers and produce significant increases in the survival of patients. DNA topoisomerases remain the most significant target of these cytotoxic drugs and constitute a growing family of nuclear enzymes that regulate DNA topology during DNA replication and(More)
The thermodynamic parameters governing the interaction of 4'-deoxy,4'-iododoxorubicin (4'-IAM) to double stranded DNA or 175 bp nucleosomes have been evaluated at different ionic strength and temperature conditions by means of fluorescence techniques. The iodo-anthracycline exhibits quite different characteristics from the parent compounds adriamycin (AM)(More)
G-Quadruplexes, noncanonical nucleic acid structures, act as silencers in the promoter regions of human genes; putative G-quadruplex forming sequences are also present in promoters of other mammals, yeasts, and prokaryotes. Here we show that also the HIV-1 LTR promoter exploits G-quadruplex-mediated transcriptional regulation with striking similarities to(More)
Vitamin D3 [1α,25-(OH)(2)D(3)], involved in the regulation of body calcium homeostasis, promotes immature myeloid precursor cells differentiation into monocytes/macrophages. In this study we compared the regulatory interaction between 1α,25-(OH)(2)D(3) and tumor necrosis factor (TNF)-α or lipopolysaccharide (LPS) in the mRNA expression of interleukin(More)