Aliases for TOP2B Gene
External Ids for TOP2B Gene
Previous GeneCards Identifiers for TOP2B Gene
This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This nuclear enzyme is involved in processes such as chromosome condensation, chromatid separation, and the relief of torsional stress that occurs during DNA transcription and replication. It catalyzes the transient breaking and rejoining of two strands of duplex DNA which allows the strands to pass through one another, thus altering the topology of DNA. Two forms of this enzyme exist as likely products of a gene duplication event. The gene encoding this form, beta, is localized to chromosome 3 and the alpha form is localized to chromosome 17. The gene encoding this enzyme functions as the target for several anticancer agents and a variety of mutations in this gene have been associated with the development of drug resistance. Reduced activity of this enzyme may also play a role in ataxia-telangiectasia. Alternative splicing of this gene results in two transcript variants; however, the second variant has not yet been fully described. [provided by RefSeq, Jul 2008]
GeneCards Summary for TOP2B Gene
TOP2B (Topoisomerase (DNA) II Beta 180kDa) is a Protein Coding gene. Among its related pathways are Doxorubicin Pathway (Cardiomyocyte Cell), Pharmacodynamics and Telomere C-strand (Lagging Strand) Synthesis. GO annotations related to this gene include protein heterodimerization activity and enzyme binding. An important paralog of this gene is TOP2A.
UniProtKB/Swiss-Prot for TOP2B Gene
Control of topological states of DNA by transient breakage and subsequent rejoining of DNA strands. Topoisomerase II makes double-strand breaks.
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 catalysing the breaking of one or two strands of DNA. Topoisomerase type I enzymes cut just one strand of the DNA double helix, and hence 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 anti-cancer 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 anticancer agents.