DNA Topoisomerases

Topoisomerases are ubiquitously expressed enzymes that overcome topological problems in genomic DNA, which can result from DNA replication, transcription and repair. Common problems such as knots and tangles are often resolved by topoisomerases.

Products
Background
Literature
Gene Data

Inhibitors

Cat No Product Name / Activity
4219 Banoxantrone dihydrochloride
Prodrug topoisomerase II inhibitor
1100 Camptothecin
DNA topoisomerase inhibitor
3203 Celastrol
Topoisomerase II inhibitor
5125 CKD 602
Topoisomerase I inhibitor
2688 CPT 11
DNA topoisomerase I inhibitor; antitumor
3857 Dexrazoxane hydrochloride
Topoisomerase II inhibitor
2252 Doxorubicin hydrochloride
Antitumor antibiotic agent. Inhibits DNA topoisomerase II
3357 Ellipticine
Antitumor and intercalating agent; inhibits DNA topoisomerase II
3260 Epirubicin hydrochloride
Inhibits DNA topoisomerase II
1226 Etoposide
Topoisomerase II inhibitor
3849 Gatifloxacin
Antibiotic; inhibits bacterial type II topoisomerase
1293 β-Lapachone
DNA topoisomerase I inhibitor
4250 Mitoxantrone dihydrochloride
Topoisomerase II inhibitor; immunosuppressive and antineoplastic agent
3135 NU 2058
Topoisomerase II inhibitor. Also inhibits cdk1 and cdk2
2684 SN 38
DNA topoisomerase I inhibitor; antitumor
4562 Topotecan hydrochloride
DNA topoisomerase I inhibitor; Camptothecin (Cat. No. 1100) analog
3863 Trovafloxacin mesylate
Antibiotic; inhibits bacterial DNA topoisomerase IV and DNA gyrase

Topoisomerases are ubiquitously expressed enzymes that overcome topological problems in genomic DNA, which can result from DNA replication, transcription and repair. Common problems such as overwinding (positive supercoiling), knots and tangles are resolved by topoisomerases by catalyzing the breaking of one or two strands of DNA.

Topoisomerase type I enzymes cut just one strand of the DNA double helix, and therefore relax supercoiling of the DNA. Four genes encode Type I topoisomerases, which include nuclear topoisomerase I (TOP1) and mitochondrial topoisomerase I (TOP1MT). Type I enzymes can also be sub-divided into Types A and B based on their different catalytic mechanism for generating single DNA strand breaks. TOP1 and TOP1MT are both type 1B since they form 3'-phosphotyrosyl bonds. Camptothecin is a natural product inhibitor of TOP1 that has led to the discovery of derivatives that are clinically used anticancer drugs. Such inhibitors trap the enzyme in a cleavage complex with DNA. Type II topoisomerases (IIA and IIB) are particular important for the disentanglement of DNA, which is overcome by generating double stranded DNA breaks. Dysregulation of type II enzymes can therefore have a potentially significant genotoxic effect. There is a broad range of topoisomerase II inhibitors that are used clinically as therapeutically in cancer.

Literature for DNA Topoisomerases

Cancer

Cancer Research Product Guide

A collection of over 750 products for cancer research, the guide includes research tools for the study of:

  • Cancer Metabolism
  • Epigenetics in Cancer
  • Receptor Signaling
  • Cell Cycle and DNA Damage Repair
  • Angiogenesis
  • Invasion and Metastasis
Cell Cycle & DNA Damage Repair

Cell Cycle & DNA Damage Repair Poster

In normal cells, each stage of the cell cycle is tightly regulated, however in cancer cells many genes and proteins that are involved in the regulation of the cell cycle are mutated or over expressed. Adapted from the 2015 Cancer Product Guide, Edition 3, this poster summarizes the stages of the cell cycle and DNA repair. It also highlights strategies for enhancing replicative stress in cancer cells to force mitotic catastrophe and cell death.

Topoisomerase Gene Data

Gene Species Gene Symbol Gene Accession No. Protein Accession No.
Topoisomerase I Human TOP1 NM_003286 P11387
Mouse Top1 NM_009408 Q04750
Rat Top1 NM_022615 Q9WUL0
Topoisomerase I (mitochondrial) Human TOP1MT NM_052963 Q969P6
Mouse Top1mt NM_028404 NP_082680
Rat Top1mt NM_001002798 Q6IM78
Topoisomerase IIα Human TOP2A NM_001067 P11388
Mouse Top2a NM_011623 Q01320
Rat Top2a NM_022183 P41516
Topoisomerase IIβ Human TOP2B NM_001068 Q02880
Mouse Top2b NM_009409 Q64511
Rat Top2b D14046 Q63177
Topoisomerase IIIα Human TOP3A NM_004618 Q13472
Mouse Top3a NM_009410 O70157
Topoisomerase IIIβ Human TOP3B NM_003935 O95985
Mouse Top3b NM_011624 Q9Z321