TOP1 Antibody – Rabbit Polyclonal

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 than undergoes passage around the unbroken 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. A chromosomal aberration involving TOP1 is found in a form of therapy-related myelodysplastic syndrome. Translocation t(11;20)(p15;q11) with NUP98. Belongs to the type IB topoisomerase family.

Protein type: Oncoprotein; Isomerase; Nucleolus; EC 5.99.1.2

Chromosomal Location of Human Ortholog: 20q12-q13.1

Cellular Component: nucleoplasm; nuclear chromosome; nucleolus; perikaryon; nucleus

Molecular Function: DNA topoisomerase (ATP-hydrolyzing) activity; protein binding; DNA binding; chromatin binding; DNA topoisomerase type I activity

Biological Process: response to drug; chromatin remodeling; circadian rhythm; DNA topological change; viral reproduction; programmed cell death; circadian regulation of gene expression; DNA replication; phosphorylation; embryonic cleavage; chromosome segregation