PMID- 10233885
OWN - NLM
STAT- MEDLINE
DCOM- 19990610
LR  - 20081121
IS  - 0006-4971 (Print)
IS  - 0006-4971 (Linking)
VI  - 93
IP  - 10
DP  - 1999 May 15
TI  - C/EBPepsilon directly interacts with the DNA binding domain of c-myb and
      cooperatively activates transcription of myeloid promoters.
PG  - 3327-37
AB  - C/EBPepsilon is essential for granulocytic differentiation. We investigated the
      role of C/EBPepsilon in the transcriptional activation of various
      myeloid-specific genes. We found that two C/EBPepsilon isoforms, p32 and p30,
      possessing transcriptional activation domains were coexpressed in myeloid cells. 
      Interestingly, isoform C/EBPepsilon p30 but not p32 was differentially
      upregulated in NB-4 promyelocytic leukemia cells treated with retinoids. Both
      isoforms bound specifically to C/EBP sites in myeloid promoters. The kd for
      C/EBPepsilon binding to the C/EBP site of the neutrophil elastase promoter was
      4.2 nmol/L. In transfection assays using the nonhematopoietic cell line, CV-1,
      the p32 isoform activated promoters from the myeloid-specific mim-1, neutrophil
      elastase, and granulocyte colony-stimulating factor (G-CSF) receptor genes by
      2.5-, 1.8-, and 1.6-fold, respectively. The p30 isoform lacked significant
      transcriptional activity, suggesting that other hematopoietic-specific factors
      were required for its function. Consistent with this prediction, transfections
      into the hematopoietic cell line Jurkat showed a 9.0- and 2.5-fold activation of 
      the mim-1 promoter by the p32 and p30 isoforms, respectively. The additional 32
      NH2-terminal residues made p32 a significantly more potent transcriptional
      activator than p30. T lymphoblasts (Jurkat cells) and immature myeloid cells (eg,
      Kcl22 cells) expressed high levels of the c-myb hematopoietic transcription
      factor. Cotransfection of c-myb with either the p32 or p30 isoform of
      C/EBPepsilon in CV-1 cells cooperatively transactivated the mim-1 promoter by 20-
      and 16-fold, respectively, and the neutrophil elastase promoter by 10-and 7-fold,
      respectively. Pulldown assays showed that each C/EBPepsilon isoform interacted
      directly with the DNA binding domain of the c-myb protein. Further studies showed
      that Kcl22 myeloid cells only contained active C/EBPepsilon, but not C/EBPalpha, 
      C/EBPbeta, or C/EBPdelta. A mutation of the C/EBP site in the neutrophil elastase
      promoter markedly decreased the transactivation of the promoter in Kcl22
      myeloblasts. These results demonstrate a role for C/EBPepsilon in regulating
      myeloid promoters, such as neutrophil elastase, probably through a direct
      interaction with c-myb.
FAU - Verbeek, W
AU  - Verbeek W
AD  - Division of Hematology/Oncology, Department of Medicine, Cedars-Sinai Medical
      Center, UCLA School of Medicine, Los Angeles CA, USA.
FAU - Gombart, A F
AU  - Gombart AF
FAU - Chumakov, A M
AU  - Chumakov AM
FAU - Muller, C
AU  - Muller C
FAU - Friedman, A D
AU  - Friedman AD
FAU - Koeffler, H P
AU  - Koeffler HP
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Blood
JT  - Blood
JID - 7603509
RN  - 0 (CCAAT-Enhancer-Binding Proteins)
RN  - 0 (Cebpe protein, mouse)
RN  - 0 (DNA-Binding Proteins)
RN  - 0 (Protein Isoforms)
RN  - 0 (Proto-Oncogene Proteins)
RN  - 0 (Proto-Oncogene Proteins c-myb)
RN  - 0 (Recombinant Fusion Proteins)
RN  - 0 (Trans-Activators)
RN  - 0 (Transcription Factors)
RN  - 142805-41-2 (CEBPE protein, human)
RN  - EC 3.4.21.37 (Leukocyte Elastase)
SB  - AIM
SB  - IM
MH  - Animals
MH  - Binding Sites
MH  - *CCAAT-Enhancer-Binding Proteins
MH  - COS Cells
MH  - Cell Nucleus/metabolism
MH  - Cloning, Molecular
MH  - DNA-Binding Proteins/metabolism
MH  - Genes, Reporter
MH  - Hematopoiesis/*genetics
MH  - Humans
MH  - Jurkat Cells
MH  - Leukocyte Elastase/genetics
MH  - Mice
MH  - Oncogenes
MH  - *Promoter Regions, Genetic
MH  - Protein Biosynthesis
MH  - Protein Isoforms/genetics/metabolism
MH  - Proto-Oncogene Proteins/*genetics/*metabolism
MH  - Proto-Oncogene Proteins c-myb
MH  - Recombinant Fusion Proteins/biosynthesis
MH  - Trans-Activators/*genetics/*metabolism
MH  - Transcription Factors/*genetics/*metabolism
MH  - *Transcription, Genetic
MH  - Transcriptional Activation
MH  - Transfection
MH  - U937 Cells
EDAT- 1999/05/11 00:00
MHDA- 1999/05/11 00:01
CRDT- 1999/05/11 00:00
PHST- 1999/05/11 00:00 [pubmed]
PHST- 1999/05/11 00:01 [medline]
PHST- 1999/05/11 00:00 [entrez]
PST - ppublish
SO  - Blood. 1999 May 15;93(10):3327-37.