Aliases for TOP3A Gene
External Ids for TOP3A Gene
Previous HGNC Symbols for TOP3A Gene
Previous GeneCards Identifiers for TOP3A 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 reducing the number of supercoils and altering the topology of DNA. This enzyme forms a complex with BLM which functions in the regulation of recombination in somatic cells. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2016]
GeneCards Summary for TOP3A Gene
TOP3A (DNA Topoisomerase III Alpha) is a Protein Coding gene. Diseases associated with TOP3A include Microcephaly, Growth Restriction, And Increased Sister Chromatid Exchange 2 and Progressive External Ophthalmoplegia With Mitochondrial Dna Deletions, Autosomal Recessive 5. Among its related pathways are Resolution of D-loop Structures through Holliday Junction Intermediates and Homologous DNA Pairing and Strand Exchange. Gene Ontology (GO) annotations related to this gene include nucleic acid binding and DNA topoisomerase activity. An important paralog of this gene is TOP3B.
UniProtKB/Swiss-Prot Summary for TOP3A 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-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand thus removing DNA supercoils. Finally, in the religation step, the DNA 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone. As an essential component of the RMI complex it is involved in chromosome separation and the processing of homologous recombination intermediates to limit DNA crossover formation in cells. Has DNA decatenation activity (PubMed:30057030). It is required for mtDNA decatenation and segregation after completion of replication, in a process that does not require BLM, RMI1 and RMI2 (PubMed:29290614).