The acute effect of RNA and DNA synthesis inhibitors on DNA topoisomerase (topo) I localization within cells was examined. Indirect immunofluorescence revealed that topo I was distributed throughout the nuclei but was concentrated in nucleoli of untreated K562 leukemia cells and A549 non-small cell lung cancer cells. Treatment with the DNA polymerase inhibitor aphidicolin did not alter this dis...

The acute effect of RNA and DNA synthesis inhibitors on DNA topoisomerase (topo) I localization within cells was examined. Indirect imiminofluorescence revealed that topo I was distributed throughout the nuclei hut was concentrated in nucleoli of untreated K562 leukemia cells and A549 non-small cell lung cancer cells. Treatment with the DNA polymerase inhibitor aphidicolin did not alter this di...

Studies were conducted to determine the possible involvement of DNA topoisomerase II (Topo II) in the induction of differentiation in two human promyeloc)tic 111 (ill leukemia cell variants that are either sus ceptible or resistant to differentiation induced by phorbol-12-myristate13-acetate (I'M \). a protein kinase C activator. The acquisition of maturation markers and changes in the activity...

Studies were conducted to determine the possible involvement of DNA topoisomerase II (Topo II) in the induction of differentiation in two human promyeloc)tic 111 (ill leukemia cell variants that are either sus ceptible or resistant to differentiation induced by phorbol-12-myristate13-acetate (I'M \). a protein kinase C activator. The acquisition of maturation markers and changes in the activity...

Class III β-tubulin (TUBB3) and Topoisomerase-II (topo-II) are considered to be the predictors of therapeutic efficacy and outcome in several types of human neoplasm. However, whether TUBB3 or topo-II may predict the response to combination chemotherapy and prognosis in patients with advanced thymic carcinoma (ATC) remains unclear. The aim of the present study was to investigate the prognostic ...

Topoisomerase II (topo II) is a ubiquitous enzyme that is essential for cell survival through its role in regulating DNA topology and chromatid separation. Topo II can be poisoned by common chemotherapeutics (such as doxorubicin and etoposide), leading to the accumulation of cytotoxic enzyme-linked DNA doublestranded breaks. In contrast, nonbreak-inducing topo II catalytic inhibitors have also ...

Ataxia telangiectasia (AT) cell lines are characterised by their hypersensitivity to ionizing radiation and bleomycin, and their failure to inhibit DNA synthesis after DNA damage. A recent report [Singh et al. (1988) Nucl. Acids Res. 16, 3919-3929] indicated that a reduction in topoisomerase II (topo II) activity was a feature of AT lymphoblast cell lines. We have studied the possible role of D...

INTRODUCTION Sumoylation is involved in nucleolus-nucleoplasm transport of DNA topoisomerase I (topo I), which may associate with changes of cellular and topo I functions. Skin fibroblasts of patients with systemic sclerosis (SSc) exhibit profibrotic cellular changes. The aims of this study were to examine the catalytic function and sumoylation of topo I in the nuclei of SSc fibroblasts, a majo...

We have demonstrated that, in Escherichia coli, quinolone antimicrobial agents target topoisomerase IV (topo IV). The inhibition of topo IV becomes apparent only when gyrase is mutated to quinolone resistance. In such mutants, these antibiotics caused accumulation of replication catenanes, which is diagnostic of a loss of topo IV activity. Mutant forms of topo IV provided an additional 10-fold ...

DNA topoisomerase I (Topo I) specifically phosphorylates arginineserine-rich (SR proteins) splicing factors and is potentially involved in pre-mRNA-splicing regulation. Using a Topo I-deficient murine B lymphoma-derived subclone (P388-45/C) selected for its resistance to high dosage of the antitumor drug camptothecin, we show that Topo I depletion results in the hypophosphorylation of SR protei...