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Updated: Oct 2, 2026

Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
GAAP-1: a transcriptional activator of p53 and IRF-1 possesses pro-apoptotic activity
Christophe Lallemand1, Marta Palmieri, Brigitte Blanchard
1Laboratory of Viral Oncology, UPR 9045 CNRS, Institut André Lwoff, F-94801 Villejuif, France.
Abstract:
The mechanisms that regulate the transcription of the tumour suppressor genes p53 and IRF-1 are poorly understood. We have characterized a 68-kDa transcription factor, GAAP-1 (gatekeeper of apoptosis activating proteins), encoded by an alternative splice product of the PRDII-BF1 gene, that recognizes a novel regulatory element within the p53 and IRF-1 promoters. Transfection of U937 cells with GAAP-1 activates p53 and IRF-1 expression and leads to apoptosis, whereas over-expression of GAAP-1 in K562 cells that lack p53 and IRF-1 induces cell differentiation. Alterations in the 6p24 locus containing the GAAP-1 gene are frequent in acute myelogenous leukemia (AML), and AML-derived cell lines display reduced GAAP-1 mRNA levels. Together, these results suggest that GAAP-1 acts as a gatekeeper at a critical point in the tumour suppressor gene pathway.
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