TOPBP1 Antibody / DNA topoisomerase II-binding protein 1, 100 ug

TOPBP1 antibody detects DNA topoisomerase II-binding protein 1, a nuclear scaffold protein essential for DNA replication initiation, checkpoint activation, and repair. The UniProt recommended name is DNA topoisomerase II-binding protein 1 (TOPBP1). This large BRCT domain-containing protein acts as a mediator between replication machinery and checkpoint kinases ATR and CHK1 to maintain genomic stability.

Functionally, TOPBP1 antibody identifies a 1522-amino-acid nuclear protein that binds DNA, replication origins, and repair complexes. TOPBP1 activates ATR kinase during replication stress, recruiting it to single-stranded DNA regions coated with replication protein A (RPA). It also coordinates DNA damage repair by interacting with RAD9-RAD1-HUS1 and other checkpoint complexes, ensuring proper S-phase progression.

The TOPBP1 gene is located on chromosome 3q22.1 and is expressed in proliferating cells across many tissues. It plays key roles in origin firing by recruiting DNA polymerase alpha/primase complexes and regulating topoisomerase II at replication forks. Through its multiple BRCT domains, TOPBP1 serves as a dynamic hub for DNA replication and checkpoint signaling.

Pathologically, overexpression or mutation of TOPBP1 has been linked to genomic instability, cancer progression, and chemoresistance. Increased TOPBP1 expression is observed in breast, ovarian, and lung cancers, where it supports high replication demand and stress tolerance. Its checkpoint-regulating activity makes it a potential target for sensitizing tumors to DNA-damaging therapies. Research using TOPBP1 antibody provides insight into replication stress response and genome surveillance mechanisms.

TOPBP1 antibody is suitable for western blotting, immunofluorescence, and chromatin immunoprecipitation to detect nuclear replication complexes. NSJ Bioreagents offers validated TOPBP1 antibody reagents designed for DNA damage repair and checkpoint signaling studies.

Structurally, TOPBP1 contains eight BRCT domains that recognize phosphorylated protein motifs, mediating interactions with DNA repair factors and replication initiators. This antibody helps elucidate how TOPBP1 integrates replication initiation and checkpoint control to preserve genome integrity.