Epigenetics controls circadian rhythms in neurons

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Epigenetics controls circadian rhythms in neurons

Brain tuberomammillary nucleus (TMN) is involved in circadian rhythm control. Neurons of this region release the neurotransmitter molecule histamine. 

DNA-packaging histone proteins are modified by histamine that influences gene expression and behavior. The enzyme transglutaminase 2 (TG2) can act as a ‘writer’, adding a histaminyl group to the fifth glutamine residue of histone H3 (producing a mark called H3Q5his). When mice are awake and in their active phase, levels of H3Q5his across the genome are high. 

TG2 also removes H3Q5his, acting as an ‘eraser’. When mice are in their inactive phase, levels of H3Q5his are low.

The authors find that rhythmic fluctuations in H3Q5his correlate with the rhythmic expression of genes that control the circadian rhythm.

https://www.nature.com/articles/s41586-024-08371-3

https://sciencemission.com/regulation-of-neural-rhythmicity