Centromere-associated topoisomerase activity in bloodstream form Trypanosoma brucei.


Obado, SO; Bot, C; Echeverry, MC; Bayona, JC; Alvarez, VE; Taylor, MC; Kelly, JM; (2011) Centromere-associated topoisomerase activity in bloodstream form Trypanosoma brucei. Nucleic acids research, 39 (3). pp. 1023-33. ISSN 0305-1048 DOI: https://doi.org/10.1093/nar/gkq839

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Abstract

Topoisomerase-II accumulates at centromeres during prometaphase, where it resolves the DNA catenations that represent the last link between sister chromatids. Previously, using approaches including etoposide-mediated topoisomerase-II cleavage, we mapped centromeric domains in trypanosomes, early branching eukaryotes in which chromosome segregation is poorly understood. Here, we show that in bloodstream form Trypanosoma brucei, RNAi-mediated depletion of topoisomerase-II?, but not topoisomerase-II?, results in the abolition of centromere-localized activity and is lethal. Both phenotypes can be rescued by expression of the corresponding enzyme from T. cruzi. Therefore, processes which govern centromere-specific topoisomerase-II accumulation/activation have been functionally conserved within trypanosomes, despite the long evolutionary separation of these species and differences in centromeric DNA organization. The variable carboxyl terminal region of topoisomerase-II has a major role in regulating biological function. We therefore generated T. brucei lines expressing T. cruzi topoisomerase-II truncated at the carboxyl terminus and examined activity at centromeres after the RNAi-mediated depletion of the endogenous enzyme. A region necessary for nuclear localization was delineated to six residues. In other organisms, sumoylation of topoisomerase-II has been shown to be necessary for regulated chromosome segregation. Evidence that we present here suggests that sumoylation of the T. brucei enzyme is not required for centromere-specific cleavage activity.

Item Type: Article
Faculty and Department: Faculty of Infectious and Tropical Diseases > Dept of Pathogen Molecular Biology
Research Centre: Neglected Tropical Diseases Network
PubMed ID: 20864447
Web of Science ID: 287257500028
URI: http://researchonline.lshtm.ac.uk/id/eprint/2629

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