Repression of the human ANT2 gene in growth-arrested human diploid cells: The role of nuclear factor 1 (NF1)

Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden.
Journal of Biological Chemistry (Impact Factor: 4.57). 09/2003; 278(33):30624-33. DOI: 10.1074/jbc.M303530200
Source: PubMed


Adenine nucleotide translocase-2 (ANT2) catalyzes the exchange of ATP for ADP across the mitochondrial membrane, thus playing an important role in maintaining the cytosolic phosphorylation potential required for cell growth. Expression of ANT2 is activated by growth stimulation of quiescent cells and is down-regulated when cells become growth-arrested. In this study, we address the mechanism of growth arrest repression. Using a combination of transfection, in vivo dimethyl sulfate mapping, and in vitro DNase I mapping experiments, we identified two protein-binding elements (Go-1 and Go-2) that are responsible for growth arrest of ANT2 expression in human diploid fibroblasts. Proteins that bound the Go elements were purified and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as members of the NF1 family of transcription factors. Chromatin immunoprecipitation analysis showed that NF1 was bound to both Go-1 and Go-2 in quiescent human diploid cells in vivo, but not in the same cells stimulated to growth by serum. NF1 binding correlated with the disappearance of ANT2 transcripts in quiescent cells. Furthermore, overexpression of NF1-A, -C, and -X in NIH3T3 cells repressed expression of an ANT2-driven reporter gene construct. Two additional putative repressor elements in the ANT2 promoter, an Sp1 element juxtaposed to the transcription start site and a silencer centered at nucleotide -332, did not appear to contribute to growth arrest repression. Thus, enhanced binding of NF1 is a key step in the growth arrest repression of ANT2 transcription. To our knowledge, this is the first report showing a role for NF1 in growth arrest.

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    • "Until now, 53 mitochondrial carriers have been identified on the human genome a nd more than half have been functionally characterized [6,7,8]. Although they play a crucial role in intermediary metabolism, only a few of them have been studied transcriptionally to some extent: the adenine nucleotide carrier [9,10,11,12,13], the uncoupling proteins [14,15,16,17,18,19], and the phosphate carrier [20] genes. Recently, the citrate carrier (CIC), encoded by SLC25A1, and the carnitine/acylcarnitine carrier (CAC), encoded by SLC25A20, have also been transcriptionally studied. "
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    Biology 03/2013; 2(1):284-303. DOI:10.3390/biology2010284
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    • "Genes regulated by NFIX have been identified and include repression of pro-angiogenic PDGFA [24] and p21, where repression surprisingly leads to growth inhibition [25]. NFIX may also slow down cell growth via downregulation of the adenine nucleotide translocase-2 gene (ANT2) [26]. In addition, NFIX has been shown to confer resistance towards transformation by nuclear but not cytoplasmic oncogenes [27]. "
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    BMC Cancer 05/2008; 8(1):138. DOI:10.1186/1471-2407-8-138 · 3.36 Impact Factor
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    • "Indeed, the overexpressions of ANT1 or ANT3 induce apoptosis while ANT2 lacks this proapoptotic activity [17,18]. ANT2 repression also leads to cell growth arrest and increases mitochondrial membrane potential from human cells as well as chemosensitized cancer cells [10,12], implying that ANT2 inhibits mitochondrial membrane permeability and acts as an antiapoptotic oncoprotein. We therefore hypothesized that ANT2 can be a promising candidate for cancer therapy based on specific molecular targeting. "
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