DOMAINS OF THE POSITIVE TRANSCRIPTION FACTOR SPECIFIC FOR THE XENOPUS 5S-RNA GENE
DOMAINS OF THE POSITIVE TRANSCRIPTION FACTOR SPECIFIC FOR THE XENOPUS 5S-RNA GENE
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DOI：
10.1016/0092-8674(84)90396-9
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发表时间：
1984-01-01
期刊：
影响因子：
64.5
通讯作者：
BROWN, DD
中科院分区：
文献类型：
--
作者：
SMITH, DR;JACKSON, IJ;BROWN, DD
非洲爪蟾（Xenopus）5SrRNA基因的50个核苷酸的内部控制区（internal control region）与40 kd [kilodalton]正转录因子相互作用，通过蛋白水解切割可将其分为3个功能域。在蛋白质的一端是一个10 kd的结构域，它是有效的RNA转录所必需的，但不是与DNA结合所必需的。这与第二个结构域相邻，该结构域与内部控制区的5“末端结合，该区域已知对蛋白质结合仅起微弱作用，但对RNA转录至关重要。这两个蛋白质结构域的去除留下了一半的蛋白质，其仅结合到控制区的3“侧，并且在促进转录方面是无活性的。定量DNA结合和体外转录实验表明，只有一个单一的分子的40 kd的因子结合到内部控制区，并且这种化学计量是足以给5S RNA转录在重建系统的最大刺激。 考虑到该因子的基本DNA接触点，以及1：1蛋白质与DNA化学计量所施加的限制，允许延伸的蛋白质分子沿沿着5S RNA基因的内部控制区线性投射到其结合位点上。
The 40 kd [kilodalton] positive transcription factor that interacts with the 50 nucleotide internal control region of 5S rRNA genes in Xenopus can be subdivided into 3 functional domains by proteolytic cleavage. At one end of the protein is a 10 kd domain that is required for efficient RNA transcription but not for binding to the DNA. This adjoins a 2nd domain that binds to the 5'' end of the internal control region, a region of the DNA known to contribute only weakly to binding the protein but one that is essential for RNA transcription. The removal of both of these protein domains leaves a half of the protein that binds only to the 3'' side of the control region and is inactive in promoting transcription. Quantitative DNA binding and in vitro transcription experiments show that only a single molecule of 40 kd factor binds to the internal control region, and that this stoichiometry is sufficient to give maximal stimulation of 5S RNA transcription in a reconstituted system. Consideration of the essential DNA contact points of the factor, taken together with the constraints imposed by a 1:1 protein to DNA stoichiometry permit the linear projection of the extended protein molecule onto its binding site along the internal control region of the 5S RNA gene.