Monsalve M, Calles B, Mencía M, Salas M, Rojo F
Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.
Mol Cell. 1997 Dec;1(1):99-107. doi: 10.1016/s1097-2765(00)80011-8.
Phage psi 29 protein p4 activates the late A3 promoter and represses the early A2c promoter, in both cases by binding upstream from RNA polymerase (RNAP) and interacting with the C-terminal domain of the RNAP alpha subunit. To investigate how this interaction leads to activation at PA3 and to repression at PA2c, mutant promoters were constructed. We show that the position of protein p4 relative to that of RNAP, which is different at each promoter, does not dictate the outcome of the interaction. Rather, in the absence of a-35 consensus box for sigma A-RNAP activation was observed, while in its presence repression occurred. The results support the view that stabilization of RNAP at the promoter over a threshold level leads to repression.
噬菌体ψ29蛋白p4激活晚期A3启动子并抑制早期A2c启动子，在这两种情况下都是通过结合RNA聚合酶（RNAP）上游并与RNAPα亚基的C末端结构域相互作用来实现的。为了研究这种相互作用如何导致PA3处的激活和PA2c处的抑制，构建了突变启动子。我们发现，蛋白p4相对于RNAP的位置在每个启动子处都不同，它并不决定相互作用的结果。相反，在没有用于σA-RNAP激活的-35共有框的情况下观察到激活，而在其存在时则发生抑制。这些结果支持了这样一种观点，即RNAP在启动子处稳定超过阈值水平会导致抑制。
