Conaway R C, Conaway J W
Department of Chemistry, University of Texas, Austin 78712-1096.
Proc Natl Acad Sci U S A. 1989 Oct;86(19):7356-60. doi: 10.1073/pnas.86.19.7356.
A transcription factor required for synthesis of accurately initiated run-off transcripts by RNA polymerase II has been purified and shown to have an associated DNA-dependent ATPase (dATPase) activity that is strongly stimulated by the TATA region of promoters. This transcription factor, designated delta, was purified more than 3000-fold from extracts of crude rat liver nuclei and has a native molecular mass of approximately 230 kDa. DNA-dependent ATPase (dATPase) and transcription activities copurify when delta is analyzed by hydrophobic interaction and ion-exchange HPLC, arguing that transcription factor delta possesses an ATPase (dATPase) activity. ATPase (dATPase) is specific for adenine nucleotides; ATP and dATP, but not CTP, UTP, or GTP, are hydrolyzed. ATPase (dATPase) is stimulated by both double-stranded and single-stranded DNAs, including pUC18, ssM13, and poly(dT); however, DNA fragments containing the TATA region of either the adenovirus 2 major late or mouse interleukin 3 promoters stimulate ATPase as much as 10-fold more effectively than DNA fragments containing nonpromoter sequences. These data suggest the intriguing possibility that delta plays a critical role in the ATP (dATP)-dependent activation of run-off transcription through a direct interaction with the TATA region of promoters.
一种RNA聚合酶II合成精确起始的连续转录本所必需的转录因子已被纯化，并显示具有一种相关的DNA依赖性ATP酶（dATP酶）活性，该活性受到启动子TATA区域的强烈刺激。这种转录因子被命名为δ，从大鼠粗制肝细胞核提取物中纯化了3000多倍，其天然分子量约为230 kDa。当通过疏水相互作用和离子交换HPLC分析δ时，DNA依赖性ATP酶（dATP酶）和转录活性共同纯化，这表明转录因子δ具有ATP酶（dATP酶）活性。ATP酶（dATP酶）对腺嘌呤核苷酸具有特异性；ATP和dATP可被水解，但CTP、UTP或GTP则不能。ATP酶（dATP酶）受到双链和单链DNA的刺激，包括pUC18、ssM13和聚（dT）；然而，含有腺病毒2主要晚期或小鼠白细胞介素3启动子TATA区域的DNA片段比含有非启动子序列的DNA片段刺激ATP酶的效率高10倍。这些数据表明了一种有趣的可能性，即δ通过与启动子的TATA区域直接相互作用，在ATP（dATP）依赖性的连续转录激活中起关键作用。
