bims-ciryme 2024-04-21 papers

Issue of 2024‒04‒21
two papers selected by
Gabriela Da Silva Xavier, University of Birmingham

Proc Natl Acad Sci U S A. 2024 Apr 23. 121(17): e2316646121

Bmal1 integrates circadian function and temperature sensing in the suprachiasmatic nucleus.

Marieke M B Hoekstra, Natalie Ness, Aina Badia-Soteras, Marco Brancaccio.

Circadian regulation and temperature dependency are important orchestrators of molecular pathways. How the integration between these two drivers is achieved, is not understood. We monitored circadian- and temperature-dependent effects on transcription dynamics of cold-response protein RNA Binding Motif 3 (Rbm3). Temperature changes in the mammalian master circadian pacemaker, the suprachiasmatic nucleus (SCN), induced Rbm3 transcription and regulated its circadian periodicity, whereas the core clock gene Per2 was unaffected. Rbm3 induction depended on a full Brain And Muscle ARNT-Like Protein 1 (Bmal1) complement: reduced Bmal1 erased Rbm3 responses and weakened SCN circuit resilience to temperature changes. By focusing on circadian and temperature dependency, we highlight weakened transmission between core clock and downstream pathways as a potential route for reduced circadian resilience.

Keywords: circadian rhythms; cold-induced pathways; suprachiasmatic nucleus; temperature sensitivity

DOI: https://doi.org/10.1073/pnas.2316646121

EMBO J. 2024 Apr 16.

Transcriptional rewiring of an evolutionarily conserved circadian clock.

Alejandra Goity, Andrey Dovzhenok, Sookkyung Lim, Christian Hong, Jennifer Loros, Jay C Dunlap, Luis F Larrondo.

Circadian clocks temporally coordinate daily organismal biology over the 24-h cycle. Their molecular design, preserved between fungi and animals, is based on a core-oscillator composed of a one-step transcriptional-translational-negative-feedback-loop (TTFL). To test whether this evolutionarily conserved TTFL architecture is the only plausible way for achieving a functional circadian clock, we adopted a transcriptional rewiring approach, artificially co-opting regulators of the circadian output pathways into the core-oscillator. Herein we describe one of these semi-synthetic clocks which maintains all basic circadian features but, notably, it also exhibits new attributes such as a "lights-on timer" logic, where clock phase is fixed at the end of the night. Our findings indicate that fundamental circadian properties such as period, phase and temperature compensation are differentially regulated by transcriptional and posttranslational aspects of the clockworks.

Keywords: Circadian Rhythms; Neurospora; Photoresponses; Synthetic Biology; Transcriptional Rewiring

DOI: https://doi.org/10.1038/s44318-024-00088-3