A schematic model of the Pch-mediated activation of the LEE1 promoter.

The nucleoid complex is composed of H-NS, StpA, Hha and YdgT. The role of YdgT is uncertain but it could be a member of the complex. In the silencing complex, DNA is folded through bridging between the proteins, and RNA polymerase might be trapped (silent). Competitive binding of Pch removes some H-NS and other proteins from the complex or inhibits the binding of them, resulting in the relaxed complex form, in which RNA polymerase can start transcription (active).