NRF-2 transcription factor is required for human TOMM20 gene expression.
TOMM20 is a subunit of the outer mitochondrial membrane translocase that plays a major role as a receptor of precursor proteins with N-terminal cleavable presequences targeted to the mitochondria. Nuclear respiratory factors 1 and 2 (NRF-1 and NRF-2) play an important role in governing nucleo-mitochondrial interactions implicated in mitochondrial biogenesis. It was recently reported that NRF-2 is critical for maintaining normal transcriptional levels of the TOMM20 gene, but the promoter of this gene is uncharacterized. We report the presence of a NRF-2 and two NRF-1 binding motifs in the 5'-flanking region of the human TOMM20 gene and provide insight into their roles for promoter activity by using chromatin immunoprecipitation experiments and reporter assays in HeLa S3 and A204 cells. We show that only NRF-2 and the proximal NRF-1 motifs are involved in the expression of the gene. The NRF-2 binding site is required to activate transcription. The proximal NRF-1 site cooperates with NRF-2 in regulating the expression of the gene. The distal NRF-1 binding site is not functional.
Blesa
José R
JR
Centro de Investigación Príncipe Felipe, Laboratory of Cell Organization, Valencia, Spain. jrblesa@cipf.es
Prieto-Ruiz
Jesús A
JA
Hernández
José M
JM
Hernández-Yago
José
J
D024506:5' Flanking Region; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D051265:NF-E2-Related Factor 1 / Q000235:genetics / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D051381:Rats; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection
D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D051265:NF-E2-Related Factor 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C084008:TOMM20 protein, human; D008156:Luciferases