Partington G A, Fuller K, Chambers T J, Pondel M
Department of Cellular and Molecular Medicine, St. George's Hospital Medical School, London SW17 0RE, UK.
Bone. 2004 Feb;34(2):237-45. doi: 10.1016/j.bone.2003.11.010.
It has been postulated that the transcription factors micropthalmia associated factor (Mitf) and PU.1 interact with the tartrate-resistant acid phosphatase (TRAP) gene promoter and activate TRAP gene expression in osteoclasts. However, studies on the interaction of these factors with the TRAP promoter employing nuclear extracts from osteoclasts and osteoclast precursors have not been reported. We therefore treated murine mononuclear phagocyte cells with various cytokines to generate cultures of osteoclasts and macrophagic cells with high or low potential to form osteoclasts. The presence of Mitf and PU.1 in nuclear extracts from these cultures and the ability of these factors to bind to the TRAP promoter was then assessed. We demonstrate that Mitf and a related factor, TFE3, are present in nuclear extracts from all cultures and bind the TRAP promoter. While PU.1 is present in nuclear extracts from all cultures, it does not significantly interact with a putative binding site in the TRAP promoter. These results suggest Mitf and PU.1 interactions with the TRAP promoter are not responsible for the specific activation of TRAP gene expression in osteoclasts.
据推测，转录因子小眼相关因子（Mitf）和PU.1与抗酒石酸酸性磷酸酶（TRAP）基因启动子相互作用，并激活破骨细胞中TRAP基因的表达。然而，尚未见利用破骨细胞和破骨细胞前体的核提取物对这些因子与TRAP启动子相互作用的研究报道。因此，我们用各种细胞因子处理小鼠单核吞噬细胞，以产生具有高或低破骨细胞形成潜能的破骨细胞和巨噬细胞培养物。然后评估这些培养物的核提取物中Mitf和PU.1的存在情况以及这些因子与TRAP启动子结合的能力。我们证明，Mitf和一个相关因子TFE3存在于所有培养物的核提取物中，并与TRAP启动子结合。虽然PU.1存在于所有培养物的核提取物中，但它与TRAP启动子中的一个假定结合位点没有明显相互作用。这些结果表明，Mitf和PU.1与TRAP启动子的相互作用并非破骨细胞中TRAP基因表达特异性激活的原因。
