C/EBP, c-Myb, and PU.1 cooperate to regulate the neutrophil elastase promoter.
The murine neutrophil elastase (NE) gene is expressed specifically in immature myeloid cells. A 91-bp NE promoter region contains three cis elements which are conserved evolutionarily and are essential for activation of the promoter in differentiating 32D cl3 myeloid cells. These elements bound c-Myb (at -49), C/EBPalpha (at -57), and PU.1 (at -82). In NIH 3T3 cells, the NE promoter was activated by c-Myb, C/EBPalpha, and PU.1, via their respective binding sites. Cooperative activation was seen by any combination of c-Myb, C/EBPalpha, and PU.1, including all three together, again via their DNA-binding sites. In CV-1 cells, but not in NIH 3T3 cells, cooperation between Myb and C/EBPalpha depended on the integrity of the PU.1-binding site. In addition to C/EBPalpha, C/EBPdelta strongly activated the NE promoter, alone or with c-Myb, but C/EBPbeta was less active. Either of C/EBPalpha's two transactivation domains cooperatively activated the promoter with c-Myb, in both NIH 3T3 and 32D c13 cells. Synergistic binding to DNA in a gel shift assay between C/EBPalpha, c-Myb, and PU.1 could not be demonstrated. Also, separation of the C/EBP- and c-Myb-binding sites by 5 or 10 bp did not prevent cooperativity. These results suggest that a coactivator protein mediates cooperative activation of the NE promoter by a C/EBP and c-Myb. These factors, together with PU.1, direct restricted expression of the NE promoter to immature myeloid cells.
Oelgeschläger
M
M
Institut für Molekularbiologie, Medizinische Hochschule Hannover, Germany.
Nuchprayoon
I
I
Lüscher
B
B
Friedman
A D
AD
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002454:Cell Differentiation; D002460:Cell Line; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000494:pharmacology / Q000502:physiology*; D004357:Drug Synergism; D004790:Enzyme Induction; D006412:Hematopoietic Stem Cells; D019272:Leukocyte Elastase; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000494:pharmacology / Q000502:physiology*; D010196:Pancreatic Elastase / Q000096:biosynthesis / Q000235:genetics*; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000494:pharmacology / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D015534:Trans-Activators / Q000494:pharmacology / Q000502:physiology*; D015533:Transcriptional Activation; D000099232:Proto-Oncogene Protein Spi-1
D022762:CCAAT-Enhancer-Binding Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D019272:Leukocyte Elastase; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D010196:Pancreatic Elastase; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1