2. Academic Validation
  3. Human mitochondrial topoisomerase I

Human mitochondrial topoisomerase I

  • Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10608-13. doi: 10.1073/pnas.191321998.
H Zhang 1,  J M Barceló,  B Lee,  G Kohlhagen,  D B Zimonjic,  N C Popescu,  Y Pommier
Affiliations

Affiliation

  • 1 Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA.
PMID: 11526219 DOI: 10.1073/pnas.191321998
Abstract

Tension generated in the circular mitochondrial genome during replication and transcription points to the need for mtDNA Topoisomerase activity. Here we report a 601-aa polypeptide highly homologous to nuclear Topoisomerase I. The N-terminal domain of this novel Topoisomerase contains a mitochondrial localization sequence and lacks a nuclear localization signal. Therefore, we refer to this polypeptide as top1mt. The pattern of top1mt expression matches the requirement for high mitochondrial activity in specific tissues. top1mt is a type IB Topoisomerase that requires divalent metal (Ca(2+) or Mg(2+)) and alkaline pH for optimum activity. The TOP1mt gene is highly homologous to the nuclear TOP1 gene and consists of 14 exons. It is localized on human chromosome 8q24.3.

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