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Polymerase II Promoter Activation: Closed Complex Formation and ATP-Driven Start Site Opening

1992; American Association for the Advancement of Science; Volume: 255; Issue: 5043 Linguagem: Inglês

10.1126/science.1310361

1095-9203

Weidong Wang, Michael Carey, Jay D. Gralla,

DNA and Nucleic Acid Chemistry

Studies on bacterial RNA polymerases have divided the initiation pathway into three steps, namely (i) promoter binding to form the closed complex; (ii) DNA melting to form an open complex, and (iii) messenger RNA initiation. Potassium permanganate was used to detect DNA melting by mammalian RNA polymerase II in vitro. Closed complexes formed in a rate-limiting step that was stimulated by the activator GAL4-VP16. Adenosine triphosphate was then hydrolyzed to rapidly melt the DNA within the closed complex to form an open complex. Addition of nucleoside triphosphates resulted in the melted bubble moving away from the start site, completing initiation.