Wilson E T, Larson D, Young L S, Sprague K U
J Mol Biol. 1985 May 25;183(2):153-63. doi: 10.1016/0022-2836(85)90209-8.
We find that tRNA gene transcription is controlled by a region much larger than the previously described internal segments known as A and B boxes. In a Bombyx mori silkworm tRNA2Ala gene, transcriptionally important sequences extend at least from -13 to +146, and thus include sequences both upstream and downstream from the 98 base-pair primary transcription unit. We show that the apparent size of this control region can be manipulated by the conditions used to measure transcription in vitro. Specifically, the use of high concentrations of templates to overcome the effect of an inhibitory substance in crude extracts can make the control region appear smaller. We propose that this finding explains much of the observed variability in the sequence requirements for transcription of different tRNA genes. If so, large size is likely to be a general feature of tRNA gene control regions.
我们发现，转运RNA（tRNA）基因转录受一个区域的控制，该区域比先前描述的被称为A盒和B盒的内部片段大得多。在家蚕的tRNA2丙氨酸基因中，转录重要序列至少从-13延伸至+146，因此包括98个碱基对初级转录单元上下游的序列。我们表明，这个控制区域的表观大小可以通过体外测量转录所使用的条件来操控。具体而言，使用高浓度模板来克服粗提物中抑制物质的影响会使控制区域显得更小。我们提出，这一发现解释了不同tRNA基因转录序列要求中观察到的许多变异性。如果是这样，大尺寸很可能是tRNA基因控制区域的一个普遍特征。
