磷酸化组蛋白H2AX(γH2AX)代表DNA双链断裂(DSB)的敏感分子标记,并与干细胞生物学有关。我们建立了小鼠胚胎干细胞(mESC)分化模型,并检查了此过程中γH2AX灶的动力学。我们的结果显示未分化mESCs中有大量的γH2AX灶,随着细胞向内皮细胞谱系分化而减少。值得注意的是,我们观察到γH2AX焦点的两种不同模式:典型的离散γH2AX焦点,与转录允许染色质标记H3K4me3和特征较差的簇状γH2AX区域共定位,仅在中间祖细胞中观察到。接下来,我们探索了mESCs对γ辐射(137Cs)的反应。暴露于γ辐射后,mESC显示细胞活力降低和γH2AX灶增加,表明放射敏感性。尽管有辐射,存活的mESC保留了它们的分化潜能。为了进一步证明我们的发现,我们研究了神经干祖细胞(NSPCs)。类似于mESC,NSPC显示与祖细胞相关的聚集的γH2AX灶和指示胚胎干细胞或分化细胞的离散的γH2AX灶。总之,我们的研究结果表明,γH2AX是DSBs的通用标记物,并可能在干细胞分化中发挥生物标记物的作用.γH2AX灶在分化mESC和NSPCs中的不同模式为分化过程中的DNA修复动力学提供了有价值的见解。揭示了干细胞中基因组完整性和细胞可塑性之间复杂的平衡。最后,在中间祖细胞中观察到的聚集的γH2AX灶是一个有趣的特征,需要进一步探索。
Phosphorylated histone H2AX (γH2AX) represents a sensitive molecular marker of DNA double-strand breaks (DSBs) and is implicated in stem cell biology. We established a model of mouse embryonic stem cell (mESC) differentiation and examined the dynamics of γH2AX foci during the process. Our results revealed high numbers of γH2AX foci in undifferentiated mESCs, decreasing as the cells differentiated towards the endothelial cell lineage. Notably, we observed two distinct patterns of γH2AX foci: the typical discrete γH2AX foci, which colocalize with the transcriptionally permissive chromatin mark H3K4me3, and the less well-characterized clustered γH2AX regions, which were only observed in intermediate progenitor cells. Next, we explored responses of
mESCs to γ-radiation (137Cs). Following exposure to γ-radiation,
mESCs showed a reduction in cell viability and increased γH2AX foci, indicative of radiosensitivity. Despite irradiation, surviving
mESCs retained their differentiation potential. To further exemplify our findings, we investigated neural stem progenitor cells (NSPCs). Similar to
mESCs, NSPCs displayed clustered γH2AX foci associated with progenitor cells and discrete γH2AX foci indicative of embryonic stem cells or differentiated cells. In conclusion, our findings demonstrate that γH2AX serves as a versatile marker of DSBs and may have a role as a biomarker in stem cell differentiation. The distinct patterns of γH2AX foci in differentiating
mESCs and NSPCs provide valuable insights into DNA repair dynamics during differentiation, shedding light on the intricate balance between genomic integrity and cellular plasticity in stem cells. Finally, the clustered γH2AX foci observed in intermediate progenitor cells is an intriguing feature, requiring further exploration.