Consider the two feed-forward loops below containing three transcription regulators A, B, and C, where A receives the input signal and C generates the output. In the so-called coherent loop (left), A activates C both directly and indirectly, whereas in an incoherent loop (right), A activates C via one route and inactivates it via the other. Answer the following question(s) based on these network motifs.

-Considering coherent and incoherent feed-forward loops, eight different designs are possible using three components and involving activation (positive) and inhibition (negative) regulation only. In all such loops, A would regulate both B and C, and B would regulate only C. How many of these designs constitute a coherent loop? Write down your answer as a number, e.g. 7.

Question

Consider the two feed-forward loops below containing three transcription regulators A, B, and C, where A receives the input signal and C generates the output. In the so-called coherent loop (left), A activates C both directly and indirectly, whereas in an incoherent loop (right), A activates C via one route and inactivates it via the other. Answer the following question(s) based on these network motifs.
 
-Considering coherent and incoherent feed-forward loops, eight different designs are possible using three components and involving activation (positive) and inhibition (negative) regulation only. In all such loops, A would regulate both B and C, and B would regulate only C. How many of these designs constitute a coherent loop? Write down your answer as a number, e.g. 7.

Quizplus · Accepted Answer

Half of the possible designs yield coherent loops.

Consider the Two Feed-Forward Loops Below Containing Three Transcription Regulators