Feedforward Loops

Recall the different types of feedforward loops. Last lecture we discussed the behavior of the C1 loop. The advantage of the C1 loop is that it protects Z from turning on due to fluctuations in X. This is called a persistence detector.

Now we will examine the behavior of some of the incoherent feedforward loops.

I1 Loop

Assume that the signals from X and Y combine in an AND NOT logic fashion to create output Z.

Transcription Rate X Y
$0$ $0$ $0$
$0$ $0$ $>0$
$k$ $>0$ $0$
$% $ $>0$ $>0$

As in the previous lecture, assume that the concentration of X quickly turns on at time $t=0$.

In summary, there are three ways to speed up response.

1. Auto-repression
2. Incoherent feedforward loop
3. Increase the degradation rate r and increase the production rate k.

Written with StackEdit.

Written on April 3, 2015