Analysis of p53 mutants for transcriptional activity.
AUTOR(ES)
Raycroft, L
RESUMO
The wild-type p53 protein functions to suppress transformation, but numerous mutant p53 proteins are transformation competent. To examine the role of p53 as a transcription factor, we made fusion proteins containing human or mouse p53 sequences fused to the DNA binding domain of a known transcription factor, GAL4. Human and mouse wild-type p53/GAL4 specifically transactivated expression of a chloramphenicol acetyltransferase reporter in HeLa, CHO, and NIH 3T3 cells. Several mutant p53 proteins, including a mouse p53 mutant which is temperature sensitive for suppression, were also analyzed. A p53/GAL4 fusion protein with this mutation was also transcriptionally active only at the permissive temperature. Another mutant p53/GAL4 fusion protein analyzed mimics the mutation inherited in Li-Fraumeni patients. This fusion protein was as active as wild-type p53/GAL4 in our assay. Two human p53 mutants that arose from alterations of the p53 gene in colorectal carcinomas were 30- to 40-fold less effective at activating transcription than wild-type p53/GAL4 fusion proteins. Thus, functional wild-type p53/GAL4 fusion proteins activate transcription, while several transformation competent mutants do so poorly or not at all. Only one mutant p53/GAL4 fusion protein remained transcriptionally active.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=361778Documentos Relacionados
- p53 isoforms can regulate p53 transcriptional activity
- p53 transcriptional activity is essential for p53-dependent apoptosis following DNA damage
- p53 transformation-related protein: detection of an associated phosphotransferase activity.
- mdm2 expression is induced by wild type p53 activity.
- Gene regulation by temperature-sensitive p53 mutants: identification of p53 response genes.