PEBP2/CBF, the murine homolog of the human myeloid AML1 and PEBP2 beta/CBF beta proto-oncoproteins, regulates the murine myeloperoxidase and neutrophil elastase genes in immature myeloid cells.
The myeloperoxidase (MPO) and neutrophil elastase genes are expressed specifically in immature myeloid cells. The integrity of a polyomavirus enhancer core sequence, 5'-AACCACA-3', is critical to the activity of the murine MPO proximal enhancer. This element binds two species, myeloid nuclear factors 1 alpha and 1 beta (MyNF1 alpha and -beta), present in 32D cl3 myeloid cell nuclear extracts. The levels of the MyNF1s increase during early 32D cl3 cell granulocytic differentiation. Both MyNF1 alpha and -beta supershift with an antiserum raised by using a peptide derived from the N terminus of polyomavirus enhancer-binding protein 2/core-binding factor (PEBP2/CBF) alpha subunit. The specific peptide inhibits these supershifts. In vitro-translated PEBP2/CBF DNA-binding domain binds the murine MPO PEBP2/CBF site. An alternate PEBP2/CBF consensus site, 5'-GACCGCA-3', but not a simian virus 40 enhancer core sequence, 5'-TTCCACA-3', binds the MyNF1s in vitro and activates a minimal murine MPO-thymidine kinase promoter in vivo. The murine neutrophil elastase gene 100-bp 5'-flanking sequences contain several functional elements, including potential binding sites for PU.1, C/EBP, c-Myb, and PEBP2/CBF. The functional element 5'-GGCCACA-3' located at positions -66 to 72 differs from the PEBP2/CBF consensus (5'-PuACCPuCA-3') only by an A-to-G transition at position 2. This DNA element binds MyNF1 alpha and -beta weakly. The N terminis of two PEBP2/CBF alpha subunit family members, PEBP2 alpha A and PEBP2 alpha B (murine AML1), are nearly identical, and 32D c13 cl3 cells contain both corresponding mRNAs. Since t(8;21), t(3;21), and inv(16), associated with myeloid leukemias, disrupt subunits of PEBP2/CBF, we speculate that the resulting oncoproteins, AML1-ETO, AML1-EAP, AML1-Evi1, and CBF beta-MYH11, inhibit early myeloid differentiation.
Nuchprayoon
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Division of Pediatric Oncology, Johns Hopkins Oncology Center, Johns Hopkins University, Baltimore, Maryland 21287.
Meyers
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S
Scott
L M
LM
Suzow
J
J
Hiebert
S
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Friedman
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D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D050659:Core Binding Factor Alpha 1 Subunit; D050657:Core Binding Factor alpha Subunits; D050658:Core Binding Factor beta Subunit; D050660:Core Binding Factors; D004268:DNA-Binding Proteins / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D066298:In Vitro Techniques; D019272:Leukocyte Elastase; D007962:Leukocytes / Q000201:enzymology*; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D010196:Pancreatic Elastase / Q000235:genetics*; D009195:Peroxidase / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics*
D050659:Core Binding Factor Alpha 1 Subunit; D050657:Core Binding Factor alpha Subunits; D050658:Core Binding Factor beta Subunit; D050660:Core Binding Factors; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; C493716:Runx2 protein, mouse; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D009195:Peroxidase; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase