Problem 3.2: Controlling an autoactivation circuit

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This problem is still a draft.

Gardner and Collins built their toggle switch so that one can manually push the circuit into a desired state via the addition of an external signal. We did not discuss how such a control mechanism might be implemented in the positive autoregulation circuit we analyzed in this chapter. Consider some possible molecular implementations of such a “control knob” that could be built into the positive autoregulation circuit to allow a user to toggle the circuit between its high and low fixed points.