TOP1 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. 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. Belongs to the type IB topoisomerase family. Endothelial cells. Note: This description may include information from UniProtKB.
Protein type: EC; Isomerase; Nucleolus; Oncoprotein
Chromosomal Location of rat Ortholog: 3q42
Cellular Component:  cytoplasm; dense fibrillar component; DNA topoisomerase complex (ATP-hydrolyzing); fibrillar center; nuclear chromosome; nucleolus; nucleoplasm; nucleus; P-body; perikaryon; protein-DNA complex; replication fork protection complex
Molecular Function:  ATP binding; chromatin binding; chromatin DNA binding; DNA binding; DNA topoisomerase type I activity; double-stranded DNA binding; protein domain specific binding; protein serine/threonine kinase activity; protein-containing complex binding; RNA polymerase II proximal promoter sequence-specific DNA binding; single-stranded DNA binding; supercoiled DNA binding
Biological Process:  animal organ regeneration; cellular response to luteinizing hormone stimulus; chromatin remodeling; chromosome segregation; circadian regulation of gene expression; circadian rhythm; DNA replication; DNA topological change; embryonic cleavage; peptidyl-serine phosphorylation; response to cAMP; response to drug; response to gamma radiation; response to temperature stimulus; rRNA transcription
Reference #:  Q9WUL0 (UniProtKB)
Alt. Names/Synonyms: Ab2-086; DNA topoisomerase 1; DNA topoisomerase I; Top1; topoisomerase (DNA) I
Gene Symbols: Top1
Molecular weight: 90,760 Da
Basal Isoelectric point: 9.35  Predict pI for various phosphorylation states
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  BioGPS  |  Pfam  |  Phospho.ELM  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene