Description_x000D_ General description_x000D_ p53 is a tumor suppressor gene expressed in a wide variety of tissues. It is a tetrameric nuclear DNA-binding phosphoprotein. The gene encoding it is localized on human chromosome 17p13.1._x000D_ Biochem/physiol Actions_x000D_ The protein has the capability to induce cell cycle arrest and has a role in DNA repair, senescence and apoptosis. It binds to Simian vacuolating virus 40 (SV40) T-antigen and human papilloma virus E6 protein._x000D_ p53 was identified as a tumor suppressor by showing that this protein has the ability to block transformation and to inhibit tumor cell growth. In addition, p53 is a transcription factor capable of regulating the expression of a subset of downstream genes. Mutation of two specific N-terminal residues in p53 (residues Leu22 and Trp23) impairs the ability of p53 to transactivate and has been correlated with its ability to bind TAFII40 and TAFII60 (or TAFII31 and TAFII70) (7, 8) suggesting that one or both of these interactions is important for activation. Mutation of residues 22 and 23 to Ala does not affect binding to TBP, although mutation of these residues to charged amino acids has been reported to disrupt the p53-TBP interaction. Different mutations in p53 gene have been characterized in a variety of human cancers. Loss or mutation of p53 function is highly correlated with tumorigenesis._x000D_ Physical form_x000D_ Clear and colorless frozen liquid solution_x000D_ Preparation Note_x000D_ Use a manual defrost freezer and avoid repeated freeze-thaw cycles. While working, please keep sample on ice.