The direct p53 target gene, FLJ11259/DRAM, is a member of a novel family of transmembrane proteins

Abstract

The tumor suppressor p53 regulates diverse biological processes primarily via activation of downstream target genes. Even though many p53 target genes have been described, the precise mechanisms of p53 biological actions are uncertain. In previous work we identified by microarray analysis a candidate p53 target gene, FLJ11259/DRAM. In this report we have identified three uncharacterized human proteins with sequence homology to FLJ11259, suggesting that FLJ11259 is a member of a novel family of proteins with six transmembrane domains. Several lines of investigation confirm FLJ11259 is a direct p53 target gene. p53 siRNA prevented cisplatin-mediated up-regulation of FLJ11259 in NT2/D1 cells. Likewise in HCT116 p53+/+ cells and MCF10A cells, FLJ11259 is induced by cisplatin treatment but to a much lesser extent in isogenic p53-suppressed cells. A functional p53 response element was identified 22.3kb upstream of the first coding exon of FLJ11259 and is shown to be active in reporter assays. In addition, chromatin immunoprecipitation assays indicate that p53 binds directly to this element in vivo and that binding is enhanced following cisplatin treatment. Confocal microscopy showed that an FLJ-GFP fusion protein localizes mainly in a punctate pattern in the cytoplasm. Overexpression studies in Cos-7, Saos2, and NT2/D1 cells suggest that FLJ11259 is associated with increased clonal survival. In summary, we have identified FLJ11259/DRAM as a p53-inducible member of a novel family of transmembrane proteins. FLJ11259/DRAM may be an important modulator of p53 responses in diverse tumor types.

An insight into the mechanistic role of p53-mediated autophagy induction in response to proteasomal inhibition-induced neurotoxicity

“…17,18 p53 itself can also induce autophagy in a DRAM (damage-regulated autophagy modulator)-dependent manner in human osteosarcoma saos-2 cell line. 19,20 In accordance with those studies, we hypothesize that proteasomal inhibition can upregulate autophagy in VM neurons and p53 may play a role in this process of induction.…”

p53 mediates mitochondria dysfunction-triggered autophagy activation and cell death in rat striatum

“…Crighton 21 has identified a p53 target gene DRAM, encoding a lysosomal protein that induces macroautophagy, as an effector of p53-mediated cell death. 41 The present study demonstrated that the p53 specific inhibitor PFT as well as the autophagy specific inhibitor 3-MA effectively blocked the 3-NP-induced induction of DRAM and LC3-II and striatal cell death. These studies suggest that p53 activates autophagy and autophagy activation contributes to 3-NP-induced striatal neuronal death.…”

Establishment and initial characterization of SOX2-overexpressing NT2/D1 cell clones

“…In order to avoid massive cell death, observed when Sox2 levels were elevated at least 4-fold above the endogenous level (Mitsui et al, 2003;Kopp et al, 2008;Tonge and Andrews, 2010), we generated cell clones with SOX2 expression driven by cytomegalovirus immediate-early promoter (CMV-IE), which exhibited weak activity in ES and EC cells (Niwa et al, 1991;Liew et al, 2007). The use of CMV-driven constitutive overexpression in NT2/D1 cells has been reported for several genes, such as pluripotency-related fibroblast growth factor-4 (FGF-4) and p27, as well as for FLJ11259/DRAM (Maerz et al, 1998;Baldassarre et al, 2000;Kerley-Hamilton et al, 2007). Using this expression system we obtained 54 resistant colonies.…”