Transcriptional regulation of the mouse cytosolic chaperonin subunit gene Ccta/t-complex polypeptide 1 by selenocysteine tRNA gene transcription activating factor family zinc finger proteins
Transcriptional regulation of the mouse cytosolic chaperonin subunit gene Ccta/t-complex polypeptide 1 by selenocysteine tRNA gene transcription activating factor family zinc finger proteins
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DOI：
10.1074/jbc.m005009200
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发表时间：
2000-09-15
影响因子：
4.8
通讯作者：
Yura, T
中科院分区：
文献类型：
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作者：
Kubota, H;Yokota, S;Yura, T
含T-复合体多肽1(CCT)的伴侣蛋白是真核生物胞浆中协助蛋白质折叠的分子伴侣，CCTA编码CCT的Cw亚基。我们发现小鼠CCTA基因的转录受硒半胱氨酸tRNA基因转录激活因子(STAF)家族锌指转录因子ZNF143和ZNF76的调控。HeLa细胞的报告基因分析表明，CCTA基因启动子含有两个18碱基长的顺式作用元件(分别命名为CCT或亚单位基因转录激活元件1和CAE2)，在-70和-20碱基上具有相似的序列。通过酵母单杂交筛选CAE1结合因子，我们分离到了人ZNF143，它可以激活硒半胱氨酸tRNA和小核RNA基因的转录。在大肠杆菌中产生的ZNF143和ZNF76的DNA结合域在凝胶迁移率改变分析中识别CAE1和CAE2元件。HeLa细胞核提取液中含有一种能被抗ZNF143抗体识别的能与CAE1和CAE2特异性结合的蛋白质。含有CAE2元件的CCTA启动子在HeLa细胞中的转录可被ZNF143和ZNF76的全长过表达所促进，但仅被其DNA结合区的过度表达所抑制。这些结果表明，STAF家族蛋白除了控制tRNA和小核RNA基因外，还控制至少一个伴侣编码基因的转录。这些RNA和伴侣基因被认为是协同调节的，以促进活跃细胞生长过程中成熟蛋白质的合成。
The chaperonin containing t-complex polypeptide 1 (CCT) is a molecular chaperone assisting in the folding of proteins in eukaryotic cytosol, and the Ccta (encoding the alpha subunit of CCT)lt-complex polypeptide 1 gene encodes the cw subunit of CCT. We show here that transcription of the mouse Ccta gene is regulated by selenocysteine tRNA gene transcription activating factor (Staf) family zinc-finger transcription factors ZNF143 and ZNF76. Reporter gene assay using HeLa cells indicated that the Ccta gene promoter contains two 18-base pair-long cis-acting elements with similar sequences at -70 and -20 base pairs (designated CCT or subunit gene transcription activating element 1 (CAE1) and CAE2, respectively). By yeast one-hybrid screening of CAE1-binding factors, we isolated human ZNF143, which is known to activate transcription of selenocysteine tRNA and small nuclear RNA genes. DNA binding domains of ZNF143 and ZNF76 produced in E. coli recognized CAE1 and CAE2 elements in electrophoretic mobility shift assay. HeLa cell nuclear extract contained a protein that specifically binds to CAE1 and CAE2 and recognized by anti-ZNF143 antibody. Transcription from a minimal Ccta promoter containing CAE2 element in HeLa cells was enhanced by overexpression of full-length ZNF143 and ZNF76 but inhibited by that of their DNA binding domains alone. These results demonstrate that the Staf family proteins control transcription of at least one of the chaperone-encoding genes besides that of tRNA and small nuclear RNA genes. These RNA and chaperone genes are suggested to be coregulated to facilitate synthesis of mature proteins during active cell growth.