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Published on: January 31, 2018
The NONO protein regulates nonclassical DNA structure: Effects on circadian genes and DNA damage
Ermanno Moriggi1, Melissa Pisteljic1, Alex Rosi-Andersen1,2
1Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
Abstract:
The DBHS protein family of Nono, PSPC1, and SFPQ regulates diverse aspects of RNA metabolism. Whether these proteins share similar functions is currently unknown. In mouse embryonic fibroblasts (MEFs), we observed around 2000 circadian and non-circadian genes regulated by Nono and PSPC1, with only 35% in common. Considering specifically circadian genes, up- or downregulation by Nono and PSPC1 depends mainly on the gene phase. We postulated a regulatory role of Nono on R-loops, the class of non-B DNA structures that form during transcription. We confirmed this by showing a broad effect of Nono on genome-wide R-loop homeostasis. Interestingly, the R-loop regulation by Nono occurs in a time-of-day dependent manner among the circadian genes. Moreover, we showed a protective role of Nono in a DNA damage cellular model that involves R-loop accumulation. Further studies are required to understand the circadian regulation of R-loops and their implications on gene regulation and disease.
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