Temperature‐controlled Rhythmic Gene Expression in Endothermic Mammals: All Diurnal Rhythms are Equal, but Some are Circadian

Abstract

The circadian clock is a cell autonomous oscillator that controls many aspects of physiology through generating rhythmic gene expression in a time of day dependent manner. In addition, in endothermic mammals body temperature cycles contribute to rhythmic gene expression. These body temperature-controlled rhythms are hard to distinguish from classic circadian rhythms if analyzed in vivo in endothermic organisms. However, they do not fulfill all criteria of being circadian if analyzed in cell culture or in conditions where body temperature of an endothermic organism can be manipulated. Here we review and compare these characteristics, discuss the core clock independent mechanism of temperature-controlled alternative splicing and highlight the requirement of double-checking rhythms that appear circadian within an endothermic organism in a system that allows temperature manipulation.

A Conserved Kinase-Based Body Temperature Sensor Globally Controls Alternative Splicing and Gene Expression

“…CLK1/4 Activity Is Highly Responsive to Physiological Temperature Changes While rhythmic AS of numerous exons is controlled by oscillating body temperature (Goldammer et al, 2018;Preußner et al, 2017;Preußner and Heyd, 2018), a temperature sensor that connects such small temperature changes with AS remains unknown. As rhythmic AS depends on body-temperaturecontrolled SR protein phosphorylation, we hypothesized that the activity of CLK kinases could be directly controlled by body temperature.…”

A Conserved Kinase-Based Body-Temperature Sensor Globally Controls Alternative Splicing and Gene Expression

“…While rhythmic AS of numerous exons is controlled by oscillating body temperature (Goldammer et al, 2018;Preußner et al, 2017;Preußner and Heyd, 2018), a temperature sensor that connects such small temperature changes with AS remains unknown. As rhythmic AS depends on body-temperaturecontrolled SR protein phosphorylation, we hypothesized that the activity of CLK kinases could be directly controlled by body temperature.…”

Alternative splicing coupled mRNA decay shapes the temperature‐dependent transcriptome

“…Additionally, there is evidence for 24‐h rhythms which is cycle independent of the central oscillator (Kornmann et al , 2007). Core clock‐independent 24‐h rhythms in GE may be difficult to discriminate from real circadian oscillations in vivo (reviewed in (Preussner & Heyd, 2018)), and our mechanistic understanding of these rhythms is limited.…”