Freytag S O, Paielli D L, Gilbert J D
Molecular Biology Research Program, Case Western Reserve University, Henry Ford Health Sciences Center, Detroit, Michigan 48202.
Genes Dev. 1994 Jul 15;8(14):1654-63. doi: 10.1101/gad.8.14.1654.
The CCAAT/enhancer-binding protein alpha (C/EBP alpha) has been implicated in the regulation of adipoblast differentiation. In this study we investigate the potential of C/EBP alpha to promote the adipogenic program in a variety of fibroblastic cells. Transduction of the C/EBP alpha gene into eight mouse fibroblastic cell lines by retroviruses and DNA transfection generates adipocyte colonies at variable frequencies. The most dramatic results are obtained with NIH-3T3 cells, in which the percentage of G418-resistant colonies that exhibit the adipocyte morphology is reproducibly > 50% when the C/EBP alpha gene is transduced by retroviruses. The ability to promote the adipogenic program requires the potent transcriptional activation domain of C/EBP alpha and is not observed with C/EBP beta. Paradoxically, in spite of its antimitogenic effects, clonal cell lines that stably express high amounts of C/EBP alpha can readily be generated. Stable expression of C/EBP alpha in BALB/c-3T3 cells dramatically enhances their ability to terminally differentiate into adipocytes. The results demonstrate that C/EBP alpha can efficiently promote the adipogenic program in a variety of mouse fibroblastic cells, including those that have little or no spontaneous capacity to undergo adipogenesis.
CCAAT/增强子结合蛋白α（C/EBPα）与脂肪母细胞分化的调控有关。在本研究中，我们探究了C/EBPα在多种成纤维细胞中促进脂肪生成程序的潜力。通过逆转录病毒和DNA转染将C/EBPα基因导入八种小鼠成纤维细胞系，可产生频率各异的脂肪细胞集落。用NIH-3T3细胞可获得最显著的结果，当通过逆转录病毒转导C/EBPα基因时，呈现脂肪细胞形态的G418抗性集落的百分比可重复性地>50%。促进脂肪生成程序的能力需要C/EBPα强大的转录激活结构域，而C/EBPβ则无此作用。矛盾的是，尽管C/EBPα具有抗有丝分裂作用，但仍能轻易产生稳定表达大量C/EBPα的克隆细胞系。C/EBPα在BALB/c-3T3细胞中的稳定表达显著增强了它们终末分化为脂肪细胞的能力。结果表明，C/EBPα可有效促进多种小鼠成纤维细胞中的脂肪生成程序，包括那些几乎没有或完全没有自发脂肪生成能力的细胞。
