The requirement of the carboxyl terminus of p53 for DNA binding and transcriptional activation depends on the specific p53 binding DNA element
Zhang, W.; Guo, X.Y.; Deisseroth, A.B.
Oncogene 9(9): 2513-2521
1994
ISSN/ISBN: 0950-9232 PMID: 8058314 Document Number: 437148
The p53 protein specifically binds DNA sequences and activates transcription. In this study, we investigated the requirement of the carboxyl (C)- or amino (N)-terminal domain of p53 for the binding and transactivation of two DNA elements, p53CON and the ribosomal gene cluster (RGC). Three human p53 mutants with deletion in either the C-terminus or N-terminus were used. Mobility-shift assays showed that the oligomerization-defective mutant p53(1-326), from which the final 67 C-terminal amino acids were deleted, retained the wild-type p53's ability to bind the p53CON element in the presence of anti-p53 monoclonal antibody PAb1801. Also, the transient transfection assays showed that the mutant p53(1-326) activated p53CON-mediated transcription. However, this mutant failed to bind the RGC element and was unable to activate RGC-mediated transcription. Thus, the requirement of the C-terminal region of p53 for DNA binding and transcription activation varies with the p53-binding DNA element under study. In contrast, the N-terminus of p53 contains a common transcription activation domain: deletion of the 80 or 159 N-terminal amino acids inactivated both p53CON- and RGC-mediated transactivation. Furthermore, mobility-shift assays did not detect any binding to p53CON- and RGC by either of the two N-terminal-deletion mutants. These results suggest that the N-terminus of p53 affects DNA binding.