Analysis of DNA binding specificity in homeodomains (1-4) of ATBF1

依赖DNA/RNA的ATPase活性与ATBF1有关，ATBF1是一种多同源结构域-锌指蛋白(Biochimica Et BiPhysica Acta)。我们研究了ATPase活性是否与ATBF1分子有关。在大肠杆菌中以GST融合蛋白的形式表达了ATBF1分子中含有ATPase A基序、同源结构域IV和锌指21的263个氨基酸片段，命名为AHZ，并对其活性进行了分析。我们发现AHZ能够水解ATP，并具有结合DNA和RNA的能力。与ATBF1相关的ATPase活性是DNA/RNA依赖的，并且是独特的，因为它需要同源结构域和锌指基序。小鼠ZFH-4蛋白包含四个同源结构域和22个锌指(Biochem)。生物群落。Res.Commun)。我们克隆了小鼠ZFHI-4基因，全长12kb，编码3,550个氨基酸的蛋白，包括4个同源结构域和22个锌指，其中包括两个假锌指基序。小鼠ZFH-4与TH…的同源性为51%对成年小鼠组织中ZFH-4转录本的RT-PCR分析表明，ZFH-4在脑、心、肺和肌肉中均有表达。在这些小鼠组织中，在扩增ZFH-4转录本的条件下，ATBF1转录本的扩增效果很差，表明ZFH-4mRNA的表达高于ATBF1mRNA.产生胃癌的甲胎蛋白(AFP)缺乏转录因子ATBF1(癌基因).我们研究了活性转录因子肝细胞核因子1(HNF1)和抑制性转录因子ATBF1对AFP产生的胃癌中AFP基因的调控。核糖核酸酶保护实验表明，胃癌细胞AFP的产生与HNF1的表达没有直接关系。在胃癌细胞中，ATBF1和AFP的表达呈明显的负相关。CAT检测显示ATBF1对AFP基因表达有直接抑制作用。临床标本免疫组织化学显示AFP产生细胞缺乏ATBF1免疫反应。我们的数据表明，ATBF1的缺失与AFP基因在胃癌中的表达有关，而ATBF1的缺失是产生AFP的胃癌的一个显著特征，并可能是其高度恶性的重要原因。较少

DNA/RNA-dependent ATPase activity is associated with ATBF1, a multiple homeodomain-zinc finger protein (Biochimica et Biophysica Acta). We examined whether ATPase activity is associated with the ATBF1 molecule. A 263-amino acid segment of the ATBF1 molecule, termed AHZ, which contains the ATPase A-motif, homeodomain IV and zinc finger 21, was expressed in E.coli as the form of GST fusion protein and analyzed for ATPase activity. We found that AHZ was able to hydorolyze ATP and had ability to bind both DNA and RNA. The ATPase activity associated with ATBF1 is DNA/RNA-dependent and unique in that it requires both homeodomain and zinc finger motifs.The mouse ZFH-4 protein contains four homeodomains and twenty-two zinc fingers (Biochem. Biophys. Res. Commun). We isolated the mouse zfhi-4 cDNA which is 12 kb long and capable of encoding a 3,550-amino acid protein containing four homeodomains and 22 zinc fingers including two pseudo zinc finger motifs. The mouse ZFH-4 is 51% homologous to th … More e mouse ATBF 1. RT-PCR analysis of zfh-4 transcripts in adult mouse tissues show that zfh-4 expression was detectable in brain, heart, lung and muscle. In these mouse tissues, ATBF1 transcripts were poorly amplified by PCR under the condtions where zfh-4 transcripts were amplified, suggesting that the expression of zfh-4 mRNA is higher than that ofATBF1 mRNA.Alpha-fetoprotein (AFP) producing gastric cancer lacks transcription factor ATBF 1 (Oncogene). We investigated AFP gene regulation in AFP-producing gastric cancer by an active transcription factor, hepatocyte nuclear factor 1 (HNF1) and a repressive transcription factor, ATBF1. Rnase protection assays revealed that the production of AFP in gastric cancer cells did not directly associate with HNF1 expression. An inverse relation between the expressions of ATBF1 and AFP was clearly observed in gastric cancer cells. CAT assays showed the direct inhibition of AFP gene expression by ATBF1. Immunohistochemistry of clinical samples revealed that AFP-producing cells lacked ATBF1 immunoreactivity. Our data suggests that the absence of ATBF1 is responsible for AFP gene expression in gastric cancer, and the absence of ATBF1 is a distinct characteristic of AFP-producing gastric cancer and might be important for its highly malignant nature. Less