A movable and regulable inactivation function within the central region of a temperature-sensitive p53 mutant

• Main Authors: Chuang, Jing-Yuan, 莊淨媛
• Other Authors: Lin,Young-Sun
• Format: Others
• Language: en_US
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/72829787018745760912

博士 === 國立臺灣大學 === 病理學研究所 === 84 === p53 is one of the most frequently mutated genes in human cancer. Naturally occurring mutations of p53 are mainly located within a region containing residues 100 to 300, and are predominantly of missense type, resulting in loss of the protein''s DNA-binding activity. Here we show that some p53 mutations also represses the p53 N-terminal activation domain. The repression activity is conformational dependent. Interestingly, the central region of a temperature-sensitive mutant p53N247I possesses a movable and regulable inacti- vation function. It represses other activities present on the same polypeptide chain without strict regard to the configuration of that polypeptide at the non-permissive temperature (37℃)butnot at the permissive one (30℃). Furthermore, this mutant p53 region exhibits no other activity and its function is independent of endogenous p53 status. Among those of human temperature-sensitive p53 mutants, the central region of p53N247I is optimal in demonstrating such an autonomous inactivation function. By deletion studies, the minimal region containing the activity is mapped to residues 101-298 of p53N247I. The central region of p53N247I appears to function in a manner that is intramolecular distance-dependent and does not alter the subcellular compartmentalization of the GAL4 fusion protein. Furthermore, de novo protein synthesis is not required for the activity of the central region of p53N247I. These results strongly suggest that the central region can be used as a movable regulatory cassette, a powerful tool for thermal regulation of chimeric proteins.