Circadian Rhythms

Variable Entrainment

Science Signaling  06 Sep 2011:
Vol. 4, Issue 189, pp. ec248
DOI: 10.1126/scisignal.4189ec248

The biochemical circuits in cells that function as biological clocks can both produce steady oscillations and be entrained by external cues to run faster or slower, or stay in sync, for example with the 24-hour light-dark cycle. Mondragón-Palomino et al. explored how such entrainment works with a synthetic cellular oscillator in bacteria that allowed them to monitor transcriptional activity of clock genes in populations of bacteria, held within a microfluidic device, when external cues vary. The results indicate that a positive feedback loop in the oscillator is critical for entrainment and that variation in the period of the oscillators among individual cells is advantageous because it ensures that at least some individuals will be entrained when environmental cues change.

O. Mondragón-Palomino, T. Danino, J. Selimkhanov, L. Tsimring, J. Hasty, Entrainment of a population of synthetic genetic oscillators. Science 333, 1315–1319 (2011). [Abstract] [Full Text]