Aliases for TOP1 Gene
External Ids for TOP1 Gene
Previous GeneCards Identifiers for TOP1 Gene
This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This enzyme catalyzes the transient breaking and rejoining of a single strand of DNA which allows the strands to pass through one another, thus altering the topology of DNA. This gene is localized to chromosome 20 and has pseudogenes which reside on chromosomes 1 and 22. [provided by RefSeq, Jul 2008]
GeneCards Summary for TOP1 Gene
TOP1 (DNA Topoisomerase I) is a Protein Coding gene. Diseases associated with TOP1 include Systemic Scleroderma and Scleroderma, Familial Progressive. Among its related pathways are SUMOylation and Irinotecan Pathway, Pharmacokinetics. Gene Ontology (GO) annotations related to this gene include core promoter sequence-specific DNA binding. An important paralog of this gene is TOP1MT.
UniProtKB/Swiss-Prot Summary for TOP1 Gene
Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand then rotates around the intact phosphodiester bond on the opposing strand, thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone (By similarity). Regulates the alternative splicing of tissue factor (F3) pre-mRNA in endothelial cells. Involved in the circadian transcription of the core circadian clock component ARNTL/BMAL1 by altering the chromatin structure around the ROR response elements (ROREs) on the ARNTL/BMAL1 promoter.
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.