PT  - JOURNAL ARTICLE
AU  - Elli Marinopoulou
AU  - Nitin Sabherwal
AU  - Veronica Biga
AU  - Jayni Desai
AU  - Antony D. Adamson
AU  - Nancy Papalopulu
TI  - HES1 protein oscillations are necessary for neural stem cells to exit from quiescence
AID  - 10.1101/2021.02.17.431655
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.17.431655
4099  - http://biorxiv.org/content/early/2021/02/17/2021.02.17.431655.short
4100  - http://biorxiv.org/content/early/2021/02/17/2021.02.17.431655.full
AB  - Quiescence is a dynamic process of reversible cell-cycle arrest. High-level sustained expression of the HES1 transcriptional repressor, which oscillates with an ultradian periodicity in proliferative neural stem cells (NSCs), is thought to mediate quiescence. However, it is not known whether this is due to a change in levels or in dynamics. Here, we induce quiescence in NSCs with BMP4, which does not increase HES1 level, and we find that HES1 continues to oscillate. To assess the role of HES1 dynamics, we express sustained HES1 under a moderate-strength promoter, which overrides the endogenous oscillations while maintaining the total HES1 level within physiological range. We find that sustained HES1 does not affect proliferation or entry into quiescence, however, exit from quiescence is impeded. Thus, oscillatory expression of HES1 is specifically required for NSCs to exit quiescence, a finding of potential importance for controlling reactivation of stem cells in tissue regeneration and cancer.Competing Interest StatementThe authors have declared no competing interest.