Characterization of a novel KRAB/C2H2 zinc finger transcription factor involved in bone development
Characterization of a novel KRAB/C2H2 zinc finger transcription factor involved in bone development
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DOI：
10.1074/jbc.m010885200
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发表时间：
2001-05-25
影响因子：
4.8
通讯作者：
Sodek, J
中科院分区：
文献类型：
--
作者：
Jheon, AH;Ganss, B;Sodek, J
成骨分化涉及一系列协调的基因表达，以确定的时空方式调节细胞增殖和基质蛋白的形成。这里我们使用微分显示识别小说锌指转录因子(AJ18)在分化诱导骨细胞在体外和体内,64 kda蛋白质编码7-kilobase mRNA,包含一个Kruppel-associated盒(带锁)域乙炔锌指图案,其次是连续11 AJ18信使rna,这也表现在肾脏和大脑,在胚胎发育监管胫骨calvariae,很少表达在新生儿和成人的动物。在体外成骨分化过程中，AJ18 mRNA在细胞接近汇合点时表达，并在骨形成时下降。利用细菌表达的his标记的AJ18进行靶检测，我们确定了5‘-CCACA-3’的一致结合序列，该序列构成了Runx2的一致元件的一部分，Runx2是成骨分化的主基因。在瞬时转染实验中，AJ18的过表达抑制runx2介导的骨钙素启动子结构的转激活，并降低骨形态发生蛋白诱导的C3H10T1/2细胞中的碱性磷酸酶活性。因此，这些研究已经确定了一种新的骨锌指转录因子，可以调节Runx2活性和成骨分化。
Osteogenic differentiation involves a cascade of coordinated gene expression that regulates cell proliferation and matrix protein formation in a defined temporo-spatial manner. Here we have used differential display to identify a novel zinc finger transcription factor (AJ18) that is induced during differentiation of bone cells in vitro and in vivo, The 64-kDa protein, encoded by a 7-kilobase mRNA, contains a Kruppel-associated box (KRAB) domain followed by 11 successive C2H2 zinc finger motifs, AJ18 mRNA, which is also expressed in kidney and brain, is developmentally regulated in embryonic tibiae and calvariae, with little expression in neonate and adult animals. During osteogenic differentiation in vitro AJ18 mRNA is expressed as cells approach confluence and declines as bone formation occurs. Using bacterially expressed, His-tagged AJ18 in a target detection assay, we identified a consensus binding sequence of 5'-CCACA-3', which forms part of the consensus element for Runx2, a master gene for osteogenic differentiation. Overexpression of AJ18 suppressed Runx2-mediated transactivation of an osteocalcin promoter construct in transient transfection assays and reduced alkaline phosphatase activity in bone morphogenetic protein-induced C3H10T1/2 cells. These studies, therefore, have identified a novel zinc finger transcription factor in bone that can modulate Runx2 activity and osteogenic differentiation.