Symbol: Top3b Name: Topoisomerase (DNA) III beta Entrez gene ID: 21976 Ensembl gene ID: ENSMUSG00000022779 Species: Mouse (Taxid: 10090) Functional description: 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 than 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 (By similarity). Possesses negatively supercoiled DNA relaxing activity. [UniProt] Observation: Homozygous disruption of Top3b results in a normal development but a shorter lifespan (by approximately 70%) accompanied by lesions in multiple organs in C57BL/6 [11331780]. Yeast Top3 physically interacts with Sgs1 [7969174]. Human TOP3A interacts with BLM [10734115; 10728666] and both TOP3A and TOP3B interact with RECQ5 [10710432]. Interventions: Assays: Organismal Lifespan Classification: Aging Relevance Analysis/Source: Homologs Edit \ Update (Admin) | Delete |
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