cis-Acting site controlling bidirectional transcription at the growth-differentiation transition in Dictyostelium discoideum.
cis-Acting site controlling bidirectional transcription at the growth-differentiation transition in Dictyostelium discoideum.
复制标题
盘基网柄菌生长-分化转变过程中控制双向转录的顺式作用位点。
DOI：
10.1128/ec.00047-06
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Loomis,WilliamF
中科院分区：
文献类型：
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作者：
Hirose,Shigenori;Payne,SamuelH;Loomis,WilliamF
一对相邻的基因，impA和dia 1，是不同的转录，但在不同阶段的生活史的盘基网柄藓。中间的654-bp区域携带顺式作用区域，这些区域对于两个方向的转录以及生长细胞中dia 1的抑制是必需的。我们集中在一个112 bp的区域近端todia 1是必不可少的双向转录。对一组内部缺失的分析表明，位置80和97之间的序列（TTTGAATTTTTTGAATTT）是关键的，并且该区域之外的碱基是重复的。在这个关键区域内的定点突变证实了该序列对于向右和向左转录的重要性。然而，插入6或24个Ts到运行的6个Ts分开的重复GAA序列在任何方向上的网站的功能几乎没有影响，这表明因素识别的半位点TTGAATT分开。位置80和97之间的碱基倒位大大降低了两个方向的表达，表明方向对于nearbyimpA基因和distaldia 1基因的表达都是至关重要的，后者距离超过500 bp。比较38个在该区域具有多个随机变异的突变体构建体表明，转录因子可以结合一系列相关序列并仍然保留功能。所有功能性构建体都指导转录，而所有非功能性构建体在两个方向上的转录都受损。似乎相同的转录复合体控制着impA和dia 1的转录。
A pair of adjacent genes,impAanddia1, are divergently transcribed but expressed at different stages in the life cycle ofDictyostelium discoideum. The intervening 654-bp region carriescis-acting regions that are essential for transcription in both directions as well as repression ofdia1in growing cells. We have focused on a 112-bp region proximal todia1that is essential for bidirectional transcription. Analyses of a set of internal deletions showed that the sequence between positions 80 and 97 (TTTGAATTTTTTGAATTT) is critical and that bases outside this region are dispensable. Site-directed mutations within this critical region confirmed the importance of this sequence for transcription both to the right and to the left. However, insertions of either 6 or 24 Ts into the run of 6 Ts separating the repeated GAA sequence had little effect on the functioning of the site in either direction, suggesting that factors recognize the half-sites TTGAATT separately. Inversion of the bases between positions 80 and 97 greatly reduced expression in both directions, indicating that orientation is critical for expression of both the nearbyimpAgene and the distaldia1gene, which is more than 500 bp away. Comparison of 38 mutant constructs with multiple random variations in the region indicated that transcription factors may bind to a range of related sequences and still retain function. All functional constructs directed transcription both leftward and rightward, while all nonfunctional constructs were impaired for transcription in both directions. It appears that the same transcription complex controls transcription of bothimpAanddia1.