Qureshi S A, Baumann P, Rowlands T, Khoo B, Jackson S P
Wellcome/CRC Institute, Cambridge, UK.
Nucleic Acids Res. 1995 May 25;23(10):1775-81. doi: 10.1093/nar/23.10.1775.
Archaea (formerly archaebacteria) comprise a domain of life that is phylogenetically distinct from both Eucarya and Bacteria. Here we report the cloning of a gene from the Archaeon Sulfolobus shibatae that encodes a protein with strong homology to the TATA binding protein (TBP) of eukaryotes. Sulfolobus shibatae TBP is, however, almost as diverged from other archaeal TBPs that have been cloned as it is from eukaryotic TBPs. DNA binding studies indicate that S.shibatae TBP recognizes TATA-like A-box sequences that are present upstream of most archaeal genes. By quantitatively immunodepleting S.shibatae TBP from an in vitro transcription system, we demonstrate that Sulfolobus RNA polymerase is capable of transcribing the 16S/23S rRNA promoter weakly in the absence of TBP. Most significantly, we show that addition of recombinant S.shibatae TBP to this immunodepleted system leads to transcriptional stimulation and that this stimulation is dependent on the A-box sequence of the promoter. Taken together, these findings reveal fundamental similarities between the transcription machineries of Archaea and eukaryotes.
古菌（以前称为古细菌）构成了一个在系统发育上与真核生物和细菌都不同的生命域。在此，我们报告了从嗜热栖热菌（Sulfolobus shibatae）克隆的一个基因，该基因编码一种与真核生物的TATA结合蛋白（TBP）具有高度同源性的蛋白质。然而，嗜热栖热菌TBP与已克隆的其他古菌TBP的差异程度几乎与它和真核生物TBP的差异程度一样大。DNA结合研究表明，嗜热栖热菌TBP识别大多数古菌基因上游存在的类似TATA的A框序列。通过从体外转录系统中定量免疫去除嗜热栖热菌TBP，我们证明在没有TBP的情况下，嗜热栖热菌RNA聚合酶能够微弱地转录16S/23S rRNA启动子。最重要的是，我们表明向这个免疫去除的系统中添加重组嗜热栖热菌TBP会导致转录刺激，并且这种刺激依赖于启动子的A框序列。综上所述，这些发现揭示了古菌和真核生物转录机制之间的基本相似性。
