Topoisomerase I Recombinant Rabbit Monoclonal Antibody [SC69-03] (ET1610-62)

UNIPROT #

P11387

PROTEIN NAME

Topoisomerase I

SYNONYMS

DNA topoisomerase 1 antibody;DNA topoisomerase I antibody;NUP98 fusion gene antibody;TOP 1 antibody;TOP I antibody;TOP1 antibody;TOP1_HUMAN antibody;TOPI antibody;Topoisomerase (DNA) I antibody;Topoisomerase 1 antibody;Topoisomerase1 antibody;TopoisomeraseI antibody;Type I DNA topoisomerase antibody

SEQUENCE SIMILARITIES

Belongs to the type IB topoisomerase family.

TISSUE SPECIFICITY

Endothelial cells.

POST-TRANSLATIONAL MODIFICATION

Sumoylated. Lys-117 is the main site of sumoylation. Sumoylation plays a role in partitioning TOP1 between nucleoli and nucleoplasm. Levels are dramatically increased on camptothecin (CPT) treatment.; Phosphorylation at Ser-506 by CK2 increases binding to supercoiled DNA and sensitivity to camptothecin.

SUBCELLULAR LOCATION

Nucleus, nucleoplasm.

FUNCTION

DNA topoisomerases play essential roles in many DNA metabolic processes including DNA repair. Topoisomerases can introduce DNA damage upon exposure to drugs that stabilize the covalent protein-DNA intermediate of the topoisomerase reaction. Lesions in DNA are also able to trap topoisomerase-DNA intermediates. DNA topoisomerase I (Top1) catalyzes the relaxation of supercoiled DNA by a mechanism of transient DNA strand cleavage characterized by the formation of a phosphotyrosyl bond between the DNA end and active site tyrosine. The antitumor agent camptothecin (CPT) reversibly stabilizes the covalent enzyme-DNA intermediate by inhibiting DNA religation. When a replication fork collides with a DNA Top1 cleavage complex, the covalently bound enzyme must be removed from the DNA 3' end before recombination-dependent replication restart. The tyrosyl-DNA phosphodiesterase Tdp1 and the structure-specific endonuclease Rad1-Rad10 function as primary alternative pathways of Top1 repair in Saccharomyces cerevisiae. In the budding yeast S. cerevisiae, DNA topoisomerases I and II can functionally substitute for each other in removing positive and negative DNA supercoils.