CCAAT/enhancer binding protein alpha is sufficient to initiate the 3T3-L1 adipocyte differentiation program.
Previous studies showed that CCAAT/enhancer binding protein alpha (C/EBP alpha) is required for differentiation of 3T3-L1 preadipocytes induced by exogenous hormonal agents. It was not possible to ascertain, however, whether C/EBP alpha alone is sufficient to induce differentiation because its antimitogenic activity precluded propagating 3T3-L1 cell lines that constitutively express C/EBP alpha at high levels. This problem was circumvented by using 3T3-L1 preadipocytes stably transfected with an isopropyl beta-D-thiogalactoside (IPTG)-inducible p42 C/EBP alpha expression vector system. IPTG-induced expression of the 42-kDa isoform of C/EBP alpha in preadipocytes caused expression of several endogenous adipocyte-specific genes (genes encoding the 422 adipose P2 protein, glucose transporter 4, and C/EBP alpha) and the accumulation of cytoplasmic triglyceride. Thus, C/EBP alpha is not only necessary but also is sufficient to trigger differentiation of growth-arrested 3T3-L1 preadipocytes without use of exogenous hormonal agents.
Lin
F T
FT
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Lane
M D
MD
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000502:physiology*; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D066298:In Vitro Techniques; D051379:Mice; D009687:Nuclear Proteins / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors / Q000502:physiology
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors