title: The promyelocytic leukemia protein represses A20-mediated transcription.
abstract: The promyelocytic leukemia (PML) protein is a tumor suppressor that is disrupted by the chromosomal translocation t(15;17), a consistent cytogenetic feature of acute promyelocytic leukemia. A role of PML in multiple pathways of apoptosis was conclusively demonstrated using PML(-/-) animal and cell culture models. In a previous study, we found that PML sensitizes tumor necrosis factor-induced apoptosis in tumor necrosis factor (TNF)-resistant U2OS cells. This finding helped to explain the mechanism of PML-induced apoptosis. The zinc finger protein A20 is a target gene of NF kappa B inducible by TNF alpha, and it is a potent inhibitor of TNF-induced apoptosis. In the this study, we demonstrated that PML is a transcriptional repressor of the A20 promoter and that PML represses A20 expression induced by TNF alpha. We showed that PML inhibits A20 transactivation through the NF kappa B site by interfering with its binding to the promoter. We also showed that stable overexpression of A20 inhibits apoptosis and caspase activation induced by PML/TNF alpha. The results of this study suggest that A20 is a downstream target of PML-induced apoptosis and supports a role of A20 in modulating cell death induced by PML/TNF alpha in TNF-resistant cells.
authors.affiliation: Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Wen-Shu
authors.initials: WS
authors.lastname: Wu
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Xu
authors.forename: Kun-Sang
authors.initials: KS
authors.lastname: Chang
mesh_terms: D017209:Apoptosis; D001483:Base Sequence; D002104:Cadmium / Q000494:pharmacology; D002884:Chromosomes, Human, Pair 15; D002886:Chromosomes, Human, Pair 17; D004268:DNA-Binding Proteins; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015473:Leukemia, Promyelocytic, Acute; D016328:NF-kappa B / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D000071156:Promyelocytic Leukemia Protein; D011506:Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014178:Translocation, Genetic; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D025521:Tumor Suppressor Proteins; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D011506:Proteins; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D025521:Tumor Suppressor Proteins; D002104:Cadmium; C070576:PML protein, human; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3