Abstract:
:CCAAT/enhancer binding protein (C/EBP) epsilon is a recently cloned member of the C/EBP family of transcription factors and is expressed exclusively in cells of hematopoietic origin. The human C/EBPepsilon gene is transcribed by two alternative promoters, Palpha and Pbeta. A combination of differential splicing and alternative use of promoters generates four mRNA isoforms, of 2.6 kb and 1.3-1.5 kb in size. These transcripts can encode three proteins of calculated molecular mass 32.2 kDa, 27.8 kDa, and 14.3 kDa. Accordingly, Western blots with antibodies specific for the DNA-binding domain, that is common to all forms, identify multiple proteins. C/EBPepsilon mRNA was greatly induced during in vitro granulocytic differentiation of human primary CD34(+) cells. Retinoic acid treatment of HL60 promyelocytic leukemia cells for 24 hr induced C/EBPepsilon mRNA levels by 4-fold, while prolonged treatment gradually reduced mRNA expression to pretreatment levels. Transient transfection experiments with expression vectors for two of the isoforms demonstrated that the 32.2-kDa protein is an activator of transcription of granulocyte colony-stimulating factor receptor promoter, while the 14.3-kDa protein is not. Thus, C/EBPepsilon is regulated in a complex fashion and may play a role in the regulation of genes involved in myeloid differentiation.
journal_name
Proc Natl Acad Sci U S Aauthors
Yamanaka R,Kim GD,Radomska HS,Lekstrom-Himes J,Smith LT,Antonson P,Tenen DG,Xanthopoulos KGdoi
10.1073/pnas.94.12.6462subject
Has Abstractpub_date
1997-06-10 00:00:00pages
6462-7issue
12eissn
0027-8424issn
1091-6490journal_volume
94pub_type
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1982-06-01 00:00:00
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更新日期:2012-12-18 00:00:00