. Author manuscript; available in PMC: 2009 Sep 1.

Published in final edited form as: Nat Rev Genet. 2005 Jul;6(7):544–556. doi: 10.1038/nrg1633

Table 1.

Examples of processes that are controlled by pacemakers and oscillators in model organisms

Organism	Oscillator or tissue with pacemaker function	Processes regulated by pacemaker	Other oscillators present?	Processes regulated by other oscillators
Synechoccus elongatus	Kai periodosome	Cell division, photosynthesis, carbohydrate synthesis, gene expression, amino-acid upatake	Predicted, but not yet described	Gene expression?
Neurospora crassa	FRQ/WC oscillator	Conidiation, gene expression	FLO	Gene expression
Neurospora crassa			Other oscillators (not yet described)	Gene expression, conidiation?
Drosophila melanogaster^*	Ventral lateral neurons	Locomotor activity	N/A	N/A
Drosophila melanogaster^*	Olfactory sensory neurons	Odour-dependent electrophysiological responses
	Autonomous oscillators in other tissues?	Gene expression, other rhythms?
Mammals	SCN	Locomotor activity, electrical firing, cytosolic calcium levels, 2-deoxyglucose uptake, neuropeptide secretion, gene expression	Heart	Heart rate, systolic blood pressure, vasodilation, gene expression
			Lung	Gene expression
			Liver	Metabolism, vesicular trafficking, detoxification, gene expression
			Kidney	Gene expression
			Fibroblasts	Gene expression
			Pineal gland	Melatonin levels
Birds	Retina	Melatonin levels	Predicted, but not yet described	Gene expression?
	SCN	Noradrenaline levels, electrical firing, sympathetic tone	Predicted, but not yet described
	Pineal gland	Melatonin levels

Oscillators in flies do not meet the classic criteria of a pacemaker; however, they are not dependent on other oscillators for their entrainment or function, and autonomously control rhythmic outputs – therefore they have pacemaker properties. FLO, FRQ-less oscillator; FRQ/WC, frequency/white-collar oscillator; SCN, suprachiasmatic nucleus.