Swart G W, van Groningen J J, van Ruissen F, Bergers M, Schalkwijk J
Department of Biochemistry, University of Nijmegen, The Netherlands.
Biol Chem. 1997 May;378(5):373-9. doi: 10.1515/bchm.1997.378.5.373.
We describe the characterization of recombinant clones for the human transcription factor CCAAT/enhancer binding protein alpha (hC/EBP alpha). The intronless hC/EBP alpha gene is almost 90% homologous to its rat and mouse counterparts. The gene copies of more distant species are less conserved, but the alignment reveals a striking homology in five regions, of which four may be involved in transactivation functions while the fifth concerns the carboxy-terminal bZip sequences (basic region and leucine zipper) mediating sequence specific DNA-binding. In addition to the usual expression sites, significant transcript levels were detected in the epidermal compartment of human skin and in rat aorta by northern analysis. The presence of hC/EBP alpha is further documented by immunohistochemical analysis of human skin biopsies and cultured keratinocytes showing the nuclear presence of the protein, notably in the suprabasal layers of the epidermis and in human keratinocytes induced to differentiate.
我们描述了人转录因子CCAAT/增强子结合蛋白α（hC/EBPα）重组克隆的特性。无内含子的hC/EBPα基因与其大鼠和小鼠对应基因几乎90%同源。更远缘物种的基因拷贝保守性较低，但序列比对显示在五个区域存在显著同源性，其中四个区域可能参与反式激活功能，而第五个区域涉及介导序列特异性DNA结合的羧基末端bZip序列（碱性区域和亮氨酸拉链）。除了常见的表达位点，通过Northern分析在人皮肤的表皮层和大鼠主动脉中检测到显著的转录本水平。人皮肤活检组织和培养的角质形成细胞的免疫组织化学分析进一步证明了hC/EBPα的存在，显示该蛋白存在于细胞核中，特别是在表皮的基底层以上各层以及诱导分化的人角质形成细胞中。
