True or false: All genes are rhythmic

Abstract

Multiple microarray studies have documented the importance of circadian regulation of gene expression in different species under many experimental conditions. However, these reports often differ with respect to the identity and total number of oscillating genes. This review explores the interrelated questions of: How many genes are oscillating within individual tissues or systems? What are the forces that drive these oscillations? What are the methodological sources contributing to the discrepancy between estimates of gene oscillation? And finally, what are the physiological and systemic implications of oscillatory gene expression with respect to circadian molecular biology? Since this remains an evolving area of investigation, this hypothetical and speculative review also highlights the potential limitations faced by the current data in the literature relating to the novel paradigm(s) proposed.

Key words::

• Circadian
• gene expression
• oscillation

Acknowledgements

The authors would like to thank all colleagues who have contributed data and thoughts in discussing rhythmic patterns of gene expression. In particular, Dr Morey Haymond, Dr Martin Young, Dr Molly Bray, Dr Jon Carlson, Dr Erica Suchman, and Dr William Black IV have provided the experimental data for unpublished reanalysis referenced in this review.

Declaration of interest: The authors declare no conflict of interest and have received no payment in preparation of this manuscript.