CCAAT ENHANCER BINDING-PROTEIN GENE PROMOTER - BINDING OF NUCLEAR FACTORS DURING DIFFERENTIATION OF 3T3-L1 PREADIPOCYTES
CCAAT ENHANCER BINDING-PROTEIN GENE PROMOTER - BINDING OF NUCLEAR FACTORS DURING DIFFERENTIATION OF 3T3-L1 PREADIPOCYTES
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DOI：
10.1073/pnas.88.6.2593
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发表时间：
1991-03-01
影响因子：
11.1
通讯作者：
LANE, MD
中科院分区：
文献类型：
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作者：
CHRISTY, RJ;KAESTNER, KH;LANE, MD
3T3-L1前脂肪细胞向脂肪细胞的分化伴随着核蛋白C/EBP （CCAAT/增强子结合蛋白）的表达增加和一组脂肪特异性基因的转录激活。我们在此报道了小鼠C/EBP基因的分离及其启动子的表征。与其在前脂肪细胞分化过程中协调转录的作用一致，C/EBP基因转录率的增加先于一些启动子被C/EBP反激活的脂肪特异性基因。来自分化和未分化3T3-L1细胞的核因子对C/EBP基因启动子DNase I的切割抑制模式（足迹）鉴定了两个差异因子结合的位点。C/EBP基因启动子中位于核苷酸-252和-239之间的一个位点与存在于分化过程中丢失或修饰的前脂肪细胞中的核因子结合。另一个位点，在核苷酸-203和-176之间，表现出不同但重叠的足迹，存在于分化和未分化细胞中的核因子。用这些位点对应的寡核苷酸进行凝胶阻滞分析，发现蛋白质-寡核苷酸复合物含有这些差异表达的核因子。分化细胞中与该位点结合的因子被鉴定为C/EBP（可能以异二聚体形式与同源亮氨酸拉链蛋白结合），表明C/EBP可能调节其自身基因的表达。
Differentiation of 3T3-L1 preadipocytes into adipocytes is accompanied by increased expression of the nuclear protein C/EBP (CCAAT/enhancer binding protein) and by transcriptional activation of a group of adipose-specific genes. We report here the isolation of the murine C/EBP gene and the characterization of its promoter. Consistent with its proposed role in coordinating transcription during preadipocyte differentiation, an increase in the rate of transcription of the C/EBP gene precedes that of several adipose-specific genes whose promoters are transactivated by C/EBP. DNase I cleavage-inhibition patterns (footprinting) of the C/EBP gene promoter by nuclear factors from differentiated and undifferentiated 3T3-L1 cells identified two sites of differential factor binding. One site in the C/EBP gene promoter between nucleotides -252 and -239 binds a nuclear factor(s) present in preadipocytes that is lost or modified upon differentiation. Another site, between nucleotides -203 and -176, exhibits different but overlapping footprints by nuclear factors present in differentiated and undifferentiated cells. Gel retardation analysis with oligonucleotides corresponding to these sites revealed protein-oligonucleotide complexes containing these differentially expressed nuclear factors. The factor present in differentiated cells that binds at this site was identified as C/EBP (possibly in heterodimeric form with a homologous leucine-zipper protein), suggesting that C/EBP may regulate expression of its own gene.