p53 is a 53 kDa nuclear phosphoprotein that acts as a tumor suppressor protein and is involved in inhibiting cell proliferation when DNA damage occurs. The gene for p53 is the most commonly mutated gene identified in human cancers. Missense mutations occur in tumors of the colon, lung, breast, ovary, bladder and several other organs. Mutant p53 is overexpressed in a variety of transformed cells. Wild-type p53 forms specific complexes with several viral oncogenes including SV40 large T, E1B from adenovirus, and E6 from human papilloma virus. It plays a role as a checkpoint protein for DNA damage during the G1/S-phase of the cell cycle. However, it is still unclear whether point mutated forms of p53 are simple null mutants and/or dominant negatively acting proteins.
DO-7 recognizes human wildtype and mutant p53. It cross-reacts with bovine p53 but does not cross-react with mouse or rat p53. DO-7 recognizes an epitope between amino acids 1-45 of the known forms of human p53. Human recombinant p53 protein was used as immunogen. Wild type p53 has a very short half-life and is usually not detectable with monoclonal antibodies in normal tissues. Clone DO-7 was initially characterized by immunoprecipitation, western blot analysis, immunohistochemistry of frozen and formalin-fixed paraffin-embedded tissue sections, and flow cytometric analysis.
Clone 27-35 is an isotype control monoclonal antibody specific for hapten dansyl (5-[dimethylamino] naphthalene-1-sulfonyl). This hapten is not expressed on human cells or human cell lines. The DO-7 and 27-35 FITC conjugates are matched in F/P ratios. The optimum F/P ratio was experimentally determined by flow cytometric analysis.
