Igarashi K, Hanamura A, Makino K, Aiba H, Aiba H, Mizuno T, Nakata A, Ishihama A
National Institute of Genetics, Department of Molecular Genetics, Shizuoka, Japan.
Proc Natl Acad Sci U S A. 1991 Oct 15;88(20):8958-62. doi: 10.1073/pnas.88.20.8958.
The role of the alpha subunit of Escherichia coli RNA polymerase in transcription activation by positive factors was investigated using two reconstituted mutant RNA polymerases (containing C-terminally truncated alpha subunits) and three positive factors [the cAMP receptor protein (CRP), OmpR, and PhoB]. The mutant RNA polymerases did not respond to transcription activation by activator proteins that bind upstream of the respective promoters. Transcription by these mutant enzymes was, however, activated in the cases where activators bind to target sites that overlap the promoter -35 region. Two different mechanisms are proposed for the positive control of transcription by activator proteins, one requiring the C-terminal domain of the alpha subunit, and the other not requiring it.
利用两种重组突变型RNA聚合酶（含有C端截短的α亚基）和三种正调控因子[cAMP受体蛋白（CRP）、OmpR和PhoB]，研究了大肠杆菌RNA聚合酶α亚基在正调控因子转录激活中的作用。这些突变型RNA聚合酶对结合在各自启动子上游的激活蛋白介导的转录激活没有反应。然而，当激活蛋白结合到与启动子-35区重叠的靶位点时，这些突变酶的转录被激活。提出了激活蛋白对转录进行正调控的两种不同机制，一种需要α亚基的C端结构域，另一种则不需要。
