Ets protein Elf-1 bidirectionally suppresses transcriptional activities of the tumor suppressor Tsc2 gene and the repair-related Nth1 gene.
Alterations in the rat tuberous sclerosis gene (Tsc2) cause renal cell carcinomas (RCCs) with complete penetrance. In this study, it was shown that the minimal core promoters of the rat Tsc2 and endonuclease III 1 (Nth1) genes, lying in a 5'-to-5' arrangement, were localized in a 0.11-kb region containing two Ets binding sites (EBSs). This region worked as a bidirectional promoter in a single reporter plasmid. Mutational inactivation of each of the two EBSs significantly reduced promoter activity. Moreover, gel shift assays revealed the presence of specific EBSs-protein complexes. These results demonstrate that some members of the Ets family positively regulate the promoter activities of the Tsc2/Nth1 genes by binding to the EBSs. We identified Elf-1 as a binding factor for EBSs through super-shift assays, and detected approximately 35 kDa bands with an EBSs-containing DNA probe by Southwestern blot analysis. Forced expression of Elf-1 in cells, however, bidirectionally suppressed the activities of the Tsc2/Nth1 promoters. Elf-1 may be a negative regulator of Tsc2/Nth1 gene expression and may compete against positive regulators for binding to the EBSs. Our observations suggest that mechanisms that inactivate Tsc2 gene expression, such as promoter suppression, may exist.
Honda
Satoshi
S
Department of Urology, Shimane Medical University, Shimane, Japan.
Kobayashi
Toshiyuki
T
Kajino
Kazunori
K
Urakami
Shinji
S
Igawa
Mikio
M
Hino
Okio
O
D000818:Animals; D001483:Base Sequence; D026501:Blotting, Southwestern; D002292:Carcinoma, Renal Cell / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000502:physiology*; D043224:Deoxyribonuclease (Pyrimidine Dimer); D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D004706:Endodeoxyribonucleases / Q000235:genetics*; D029968:Escherichia coli Proteins; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D016147:Genes, Tumor Suppressor; D006801:Humans; D007680:Kidney Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D010957:Plasmids; D011401:Promoter Regions, Genetic; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection; D014402:Tuberous Sclerosis / Q000235:genetics; D000077005:Tuberous Sclerosis Complex 2 Protein; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D017931:DNA Primers; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C000624653:TSC2 protein, human; D014157:Transcription Factors; C000624655:Tsc2 protein, rat; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; D004247:DNA; D008156:Luciferases; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; C468347:NTHL1 protein, human