title: Intracellular distribution of DNA topoisomerase I in fibroblasts from patients with Fanconi's anaemia.
abstract: The activity of DNA topoisomerase I(DNA nicking-closing enzyme) was analysed in cytoplasmic and nuclear extracts of six independently derived Fanconi and four normal fibroblast cell lines. In all experiments the total cellular activity was predominantly found in the nuclear extracts (88-100%). In addition, a minor proportion of the enzyme (up to 12%) was randomly present in some of the cytoplasmic fractions of both Fanconi and normal fibroblasts. These results indicate that Fanconi's anaemia is probably not due to or accompanied by a maldistribution of topoisomerase I between nuclei and cytoplasm.
mesh_terms: D000741:Anemia, Aplastic / Q000201:enzymology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D011088:DNA Ligases / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D005199:Fanconi Anemia / Q000201:enzymology* / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans
chemical_list: D004264:DNA Topoisomerases, Type I; D011088:DNA Ligases