Feedback loops help keep the Neurospora biological clock stable

Interlocked feedback loops may play a crucial role in regulating circadian rhythms.

• WC-1 and WC-2 proteins activate the transcription of the frq gene.
• FRQ protein represses its own transcription while also activating the expression of WC-1 and WC-2.
• The interaction between these proteins results in two interlocked feedback loops: one negative and one positive.
• The robustness and stability of the circadian clock are influenced by the levels of WC-1 and WC-2.
• Higher levels of WC-1 and WC-2 are associated with increased FRQ oscillation and more stable rhythms.
• Despite fluctuations in the levels of these proteins, the circadian period remains constrained within a narrow range.

Simplified