Sequence-specific DNA binding of the proto-oncoprotein ets-1 defines a transcriptional activator sequence within the long terminal repeat of the Moloney murine sarcoma virus.
The ets proto-oncogene family is a group of sequence-related genes whose normal cellular function is unknown. In a study of cellular proteins involved in the transcriptional regulation of murine retroviruses in T lymphocytes, we have discovered that a member of the ets gene family encodes a sequence-specific DNA-binding protein. A mouse ets-1 cDNA clone was obtained by screening a mouse thymus cDNA expression library with a double-stranded oligonucleotide probe representing 20 bp of the Moloney murine sarcoma virus (MSV) long terminal repeat (LTR). The cDNA sequence has an 813-bp open reading frame (ORF) whose predicted amino acid sequence is 97.6% identical to the 272 carboxy-terminal amino acids of the human ets-1 protein. The ORF was expressed in bacteria, and the 30-kD protein product was shown to bind DNA in a sequence-specific manner by mobility-shift assays, Southwestern blot analysis, and methylation interference. A mutant LTR containing four base pair substitutions in the ets-1 binding site was constructed and was shown to have reduced binding in vitro. Transcriptional efficiency of the MSV LTR promoter containing this disrupted ets-1 binding site was compared to the activity of a wild-type promoter in mouse T lymphocytes in culture, and 15- to 20-fold reduction in expression of a reporter gene was observed. We propose that ets-1 functions as a transcriptional activator of mammalian type-C retroviruses and speculate that ets-related genes constitute a new group of eukaryotic DNA-binding proteins.
Gunther
C V
CV
Department of Cellular, Viral, and Molecular Biology, University of Utah School of Medicine, Salt Lake City 84132.
Nye
J A
JA
Bryner
R S
RS
Graves
B J
BJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002478:Cells, Cultured; D004279:DNA, Viral / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D008980:Moloney murine sarcoma virus / Q000235:genetics*; D005810:Multigene Family; D000090063:Proto-Oncogene Mas; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D011519:Proto-Oncogenes; D012091:Repetitive Sequences, Nucleic Acid; D009053:Sarcoma Viruses, Murine / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004279:DNA, Viral; C494041:ETS1 protein, human; C494042:Ets1 protein, mouse; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors