Baquero Pérez Manuela, Laenen Gertjan, Loïodice Isabelle, Garnier Mickaël, Szachnowski Ugo, Morillon Antonin, Ruault Myriam, Taddei Angela
UMR 3664 Nuclear Dynamics, CNRS, Institut Curie, Université PSL, Sorbonne University, 75248 Paris, France.
UMR 3244 DIG-Cancer, CNRS, Institut Curie, Université PSL, Sorbonne University, 75248 Paris, France.
Genome Res. 2025 Sep 10. doi: 10.1101/gr.279874.124.
Quiescent (Q) cells are seemingly inactive, developmentally arrested cells, whose universal characteristic is the ability to promptly re-enter the cell cycle upon sensing of external cues. Q cells are responsive to the environment and flexible enough to adapt to available resources. In budding yeast, quiescent nuclear features are drastically distinct from those observed in nutrient replete conditions: The nuclear volume is reduced; the telomeres relocate from the nuclear periphery to the center of the nucleus into a hypercluster; chromatin is found in a compacted, hypoacetylated state; and transcription is globally shutdown. Yet, Q cells can restart transcription within minutes of refeeding. Here, we follow the global decrease of transcription in sorted, developing Q populations and its reactivation upon release. We find that transcription and telomere clustering dynamics in and out of quiescence are independent events. We report a genome-wide redistribution of the transcription machinery as cells progress into quiescence. Although most genes are shut down, 3% of coding genes remain active. Furthermore, RNA polymerase II (RNAPII) accumulates at one-third of gene promoters. The corresponding genes are highly enriched among those showing a high level of transcription and high frequency of expression in individual cells, shortly after cells are refed, as monitored by single-cell RNA-seq. Our results point toward a role for quiescent-specific RNAPII distribution to ensure a rapid and robust transcriptional response upon return to growth.
静止(Q)细胞看似不活跃,处于发育停滞状态,其普遍特征是在感知外部信号时能够迅速重新进入细胞周期。Q细胞对环境有反应,并且足够灵活以适应可用资源。在芽殖酵母中,静止期的核特征与营养丰富条件下观察到的核特征截然不同:核体积减小;端粒从核周边重新定位到核中心形成一个超簇;染色质处于压缩的低乙酰化状态;转录整体关闭。然而,Q细胞在重新投喂后几分钟内就能重新启动转录。在这里,我们追踪了分选的、正在发育的Q群体中转录的整体下降及其在释放时的重新激活。我们发现静止期内外的转录和端粒聚类动态是独立事件。我们报告了随着细胞进入静止期,转录机制在全基因组范围内的重新分布。虽然大多数基因被关闭,但3%的编码基因仍保持活跃。此外,RNA聚合酶II(RNAPII)在三分之一的基因启动子处积累。通过单细胞RNA测序监测发现,在细胞重新投喂后不久,相应的基因在那些在单个细胞中显示出高水平转录和高表达频率的基因中高度富集。我们的结果表明静止期特异性的RNAPII分布在确保细胞恢复生长时快速而强大的转录反应中发挥作用。