This gene encodes tumor protein p53, which responds to diverse cellular stresses to regulate target genes that induce cell cycle arrest, apoptosis, senescence, DNA repair, or changes in metabolism. p53 protein is expressed at low level in normal cells and at a high level in a variety of transformed cell lines, where it\'s believed to contribute to transformation and malignancy. p53 is a DNA-binding protein containing transcription activation, DNA-binding, and oligomerization domains. It is postulated to bind to a p53-binding site and activate expression of downstream genes that inhibit growth and/or invasion, and thus function as a tumor suppressor. Mutants of p53 that frequently occur in a number of different human cancers fail to bind the consensus DNA binding site, and hence cause the loss of tumor suppressor activity. Alterations of this gene occur not only as somatic mutations in human malignancies, but also as germline mutations in some cancer-prone families with Li-Fraumeni syndrome. Multiple p53 variants due to alternative promoters and multiple alternative splicing have been found. These variants encode distinct isoforms, which can regulate p53 transcriptional activity.

Human wild-type p53 protein is composed of 393 amino acid residues with several distinct regions. The N-terminal activation domain allows p53 protein to recruit the basal transcription machinery and activate the expression of target genes, whereas the core domain binds to target DNA in a sequence-specific manner and the majority of mutations found in human tumors occur in the region of the gene encoding this domain (1-3). The C-terminal domain is composed of predominantly basic residues and modification of the C-terminal basic domain, including acetylation, glycosylation and phosphorylation, is an essential mechanism for regulating p53 function (4-6).

This mutant p53 protein, with the deletion of the C-terminus 51 residues including the entire basic domain and a portion of the tetramerization domain, can be used as a unique tool to study specific functions of p53 related to the C-terminus.

• gel mobility shift assay or for a DNase I footprinting assay in the presence of double stranded DNA containing a consensus p53-binding sequence [5’-PuPuPuC(A/T)(T/A)GPyPyPy-3’]
• in vitro transcription assay
• protein-protein interaction assay
• for cell growth assay

1 unit equals to 1 nanogram of purified protein. 1 unit is sufficient for a gel mobility shift assay in a 20 µl reaction; 50 units are sufficient for reconstituted transcription assay and 100 units are sufficient for a protein-protein interaction assay.

~ 95% as determined by SDS-PAGE