Mutations affecting two adjacent amino acid residues in the alpha subunit of RNA polymerase block transcriptional activation by the bacteriophage P2 Ogr protein.
Mutations affecting two adjacent amino acid residues in the alpha subunit of RNA polymerase block transcriptional activation by the bacteriophage P2 Ogr protein.
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影响 RNA 聚合酶 α 亚基中两个相邻氨基酸残基的突变会阻止噬菌体 P2 Ogr 蛋白的转录激活。
DOI：
10.1128/jb.176.24.7430-7438.1994
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发表时间：
1994
影响因子：
3.2
通讯作者：
Christie,GE
中科院分区：
文献类型：
--
作者：
Ayers,DJ;Sunshine,MG;Six,EW;Christie,GE
噬菌体P2 ogr基因产物是P2晚期启动子转录的正调控因子。ogr基因最初被定义为补偿突变，这种突变克服了宿主突变rpoA109对P2生长的阻碍，rpoA109是编码RNA聚合酶α亚基的基因。DNA序列分析证实，该突变影响α亚基的c端区域，将位置290的亮氨酸残基改变为组氨酸（rpoAL290H）。我们使用报告质粒系统筛选其他先前描述的rpoA突变体对P2晚期启动子激活的影响，并确定了第二个阻断P2晚期转录的等位基因rpoA155。这个突变位于rpoAL290H的上游，将289位的亮氨酸残基改变为苯丙氨酸（rpoAL289F）。rpoAL289F突变的作用不受rpoal290h代偿性P2 ogr突变的抑制。P2 ogr突变体克服了rpoAL289F所施加的阻滞，并进行了分离和表征。我们的结果与Ogr与RNA聚合酶α亚基之间的直接相互作用一致，并支持α C端内转录因子接触位点离散且紧密聚集的模型。
The bacteriophage P2 ogr gene product is a positive regulator of transcription from P2 late promoters. The ogr gene was originally defined by compensatory mutations that overcame the block to P2 growth imposed by a host mutation, rpoA109, in the gene encoding the alpha subunit of RNA polymerase. DNA sequence analysis has confirmed that this mutation affects the C-terminal region of the alpha subunit, changing a leucine residue at position 290 to a histidine (rpoAL290H). We have employed a reporter plasmid system to screen other, previously described, rpoA mutants for effects on activation of a P2 late promoter and have identified a second allele, rpoA155, that blocks P2 late transcription. This mutation lies just upstream of rpoAL290H, changing the leucine residue at position 289 to a phenylalanine (rpoAL289F). The effect of the rpoAL289F mutation is not suppressed by the rpoAL290H-compensatory P2 ogr mutation. P2 ogr mutants that overcome the block imposed by rpoAL289F were isolated and characterized. Our results are consistent with a direct interaction between Ogr and the alpha subunit of RNA polymerase and support a model in which transcription factor contact sites within the C terminus of alpha are discrete and tightly clustered.