Tumor suppressor p53 can participate in transcriptional induction of the GADD45 promoter in the absence of direct DNA binding
Authors: I T Chen
Q Zhan
A J Fornace Jr
M J Antinore
Journal: Molecular and Cellular Biology (1998)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: GADD45 gene; p53; stress responsiveness; promoter; GC-rich motif
Affiliations: Division of Basic Sciences, National Cancer Institute, Bethesda, Maryland 20892-4255, USA.

Abstract:  The GADD45 gene is a growth arrest-associated gene that is induced by certain DNA-damaging agents and other stresses, such as starvation, in all mammalian cells. In addition to a strong p53-binding element in an intronic sequence, we have recently found that p53, while not required or sufficient alone, may contribute to the stress responsiveness of the promoter. Much of the responsiveness was localized to a GC-rich motif in the proximal promoter which contains multiple Egr1 sites and a larger WT1 site; this 20-bp WT1 motif is identical to the WT1-binding site in the PDGF-A gene. In extracts from a human breast carcinoma cell line expressing p53 and WT1, which is known to associate with p53 in vivo, evidence was obtained that these proteins are in a complex that binds this 20-bp element. A combination of p53 and WT1 expression vectors strongly induced a GADD45-reporter construct, while mutation of the WT1-Egr1 site in the promoter prevented this induction. Abrogation of p53 function by a dominant-negative vector or abrogation of WT1 function by an antisense vector markedly reduced the induction of this promoter. Since p53 does not bind directly to the promoter, these results indicate that p53 can contribute to the positive regulation of a promoter by protein-protein interactions. 

Retracted: No

PubPeer comments:
 Figure 8C: one image should be U2OS group, right? ![file] , 
 Dear Dr. Takifugu Stictonotus, We appreciate your comments. In this assay, we examined the Gadd45 induction following WT1 inducible expression. We employed U2OS line UB27, which contains tetracycline inducible WT1. RNA was isolated from UB27 cells cultured with tetracycline (Tet +) and the UB27 cells where the tetracycline had been removed 4 hours earlier (Tet -). To ensure the accuracy of Gadd45 induction by WT1, two pairs of RNA samples from UB27 cells were prepared separately in this experiment. Afterward, RNA was hybridized with Gadd45 and GAPD probes. We described these details in the legend of figure 8C. Therefore, there were no errors in the labeling of cell line in Figure 8C. However, we thank you for your interest in this issue. , 
 Dear Dr. Takifugu Stictonotus, We appreciate your comments. In this assay, we examined the Gadd45 induction following WT1 inducible expression. We employed U2OS line UB27, which contains tetracycline inducible WT1. RNA was isolated from UB27 cells cultured with tetracycline (Tet +) and the UB27 cells where the tetracycline had been removed 4 hours earlier (Tet -). To ensure the accuracy of Gadd45 induction by WT1, two pairs of RNA samples from UB27 cells were prepared separately in this experiment. Afterward, RNA was hybridized with Gadd45 and GAPD probes. We described these details in the legend of figure 8C. Therefore, there were no errors in the labeling of cell line in Figure 8C. However, we thank you for your interest in this issue. ,