Activation and centromeric localization of CCAAT/enhancer-binding proteins during the mitotic clonal expansion of adipocyte differentiation.
Hormonal induction of 3T3-L1 preadipocytes triggers a cascade of events that initiate differentiation into adipocytes. CCAAT/enhancer-binding proteins beta and delta (C/EBPbeta/delta) are expressed early in the differentiation program, but are not immediately active. After a long lag, C/EBPbeta/delta become competent to bind to the C/EBP regulatory element in the C/EBPalpha gene promoter, C/EBPalpha being a transcriptional activator of numerous adipocyte genes. As C/EBPbeta/delta acquire binding activity, they become localized to centromeres as preadipocytes synchronously enter S phase at the onset of mitotic clonal expansion. Localization to centromeres occurs through C/EBP consensus-binding sites in centromeric satellite DNA. C/EBPalpha, which is antimitotic, becomes centromere-associated much later in the differentiation program as mitotic clonal expansion ceases and the cells become terminally differentiated.
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Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 USA.
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D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000502:physiology*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins; D002453:Cell Cycle / Q000502:physiology*; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000502:physiology; D002503:Centromere / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D007700:Kinetics; D051379:Mice; D008938:Mitosis; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D016196:S Phase; D014157:Transcription Factors
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors