53BP1 (p53 binding protein 1) was originally thought to be an enhancer for p53 transcriptional, but later studies have demonstrated that it is actually a substrate for ataxia telangiectasia mutated (ATM). 53BP1 is a classic late DNA damage response (DDR) marker that is present during the cell cycle phases of telophase and cytokinesis (within mitotic mammalian cells). Grenier et al performed DNA damage experiments with the 53BP1 antibody in a rat embryo system that contained damaged paternal genomes exposed to the anticancer alkylating agent cyclophosphamide (1). These researchers determined that this metric of damage repair was useful in analyzing embryo quality as well as developmental potential of the affected tissue. Further cell cycle studies with the 53BP1 antibody focused on comparing the competitive differences between 53BP1 and BRCA1 regulation in cohorts of cycling and non-cycling cells (2). Researchers from Croke's group at St Louis University's Medical School determined that breast cancer cells use an endogenous mechanism of balancing the two systems to maintain genome stability and continued growth. Naim's group published in Nature Cell Biology that the proteins ERCC1 and MUS81-EME1 co-localize to common fragile sites (CFSs) within mitotic chromosomes, thus promoting sister chromatid separation (3). Those researchers performed immunofluorescent and immunohistochemical studies with the 53BP1 antibody to map these key chromosomal rearrangements. Martin's group in Melbourne also relied upon the 53BP1 antibody to help them generate detailed statistical analyses of the kinetics, distribution, and localization of DNA repair foci in their radiosensitivity studies in irradiated cells (4). These studies helped to expand the dimensions of their novel rapid assay with regards to assigning criteria for defining experimental endpoints, as well as helping to validate its predictive abilities. Flach's group published recently in Nature their findings from hematopoietic stem cells (HSCs) that replicative stress helps to drive the functional decline seen with aging; their results required use of the 53BP1 antibody (5).
Novus Biologicals offers 53BP1 reagents for your research needs including:
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