Hibernation, Thermogenesis, Brown Fat, and BAT Activation: Elevated Transcript Level in Torpor Cycle Is Caused by Enhanced Transcript Stabilization; Temperature-Sensitive Mechanism Protects Subset of Transcripts from Bulk Degradation

During hibernation, animals cycle between torpor and arousal. These cycles involve dramatic, but poorly understood echanisms of dynamic physiological regulation at the level of gene expression. In each cycle, brown adipose tissue (BAT) drives periodic arousal from torpor by generating essential heat. We applied digital transcriptome analysis to precisely timed samples to identify molecular pathways that underlie the intense activity cycles of hibernator BAT. Paradoxically, a cohort of transcripts increased during torpor, paradoxical because transcription effectively ceases at these low temperatures. A new study, published online on January 27, 2015 in an open-access article in the journal eLife, shows that this increase occurs not by elevated transcription, but rather by enhanced stabilization associated with maintenance and/or extension of long poly(A) tails. The study further reported that mathematical modeling supports a temperature-sensitive mechanism to protect a subset of transcripts from ongoing bulk degradation instead of increased transcription. The authors reported that his subset was enriched in a C-rich motif and genes required for BAT activation, suggesting a model and mechanism to prioritize translation of key proteins for thermogenesis. The eLife article was entitled,”Enhanced Stability and Polyadenylation of Select mRNAs Support Rapid Thermogenesis in the Brown Fat of Hibernators.” The authors were scientists from the University of Colorado School of Medicine, the Colorado School of Mines, and the HudsonAlpha Institute for Biotechnology. [eLife article]
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