Development of the circadian oscillator during differentiation of mouse embryonic stem cells in vitro
Development of the circadian oscillator during differentiation of mouse embryonic stem cells in vitro
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DOI：
10.1073/pnas.0913256107
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发表时间：
2010-02-23
影响因子：
11.1
通讯作者：
Uchiyama, Yasuo
中科院分区：
文献类型：
--
作者：
Yagita, Kazuhiro;Horie, Kyoji;Uchiyama, Yasuo
哺乳动物昼夜节律产生的分子振荡在个体发育过程中逐渐发展。然而，哺乳动物细胞昼夜节律振荡器形成的发育过程仍然未知。在已分化的体细胞中，由生物钟基因组成的转录-翻译反馈环（TTFL）引起分子昼夜节律振荡。使用生物发光成像系统来监测时钟基因的表达，我们在这里表明，昼夜生物发光节律在小鼠胚胎干细胞（ES）中没有检测到，ES细胞可能缺乏TTFL调节时钟基因的表达。在无母体因素的小鼠ES细胞分化培养过程中，诱导了生物钟振荡。此外，通过表达Sox 2、KIf 4、Oct 3/4和c-Myc基因（它们是产生诱导多能干细胞（iPS）的因子）对分化的细胞进行重编程，导致昼夜节律振荡的再次消失。这些结果表明，在体外ES细胞分化过程中，一个内在的程序控制着昼夜振荡器的形成。使用培养的ES细胞的细胞分化和重编程系统使我们能够观察生物钟的形成过程，并可能有助于设计新的策略来了解负责哺乳动物分子振荡器组织的关键机制。
The molecular oscillations underlying the generation of circadian rhythmicity in mammals develop gradually during ontogenesis. However, the developmental process of mammalian cellular circadian-oscillator formation remains unknown. In differentiated somatic cells, the transcriptional-translational feedback loops (TTFL) consisting of clock genes elicit the molecular circadian oscillation. Using a bioluminescence imaging system to monitor clock gene expression, we show here that the circadian bioluminescence rhythm is not detected in the mouse embryonic stem (ES) cells, and that the ES cells likely lack TTFL regulation for clock gene expression. The circadian clock oscillation was induced during the differentiation culture of mouse ES cells without maternal factors. In addition, reprogramming of the differentiated cells by expression of Sox2, KIf4, Oct3/4, and c-Myc genes, which were factors to generate induced pluripotent stem (iPS) cells, resulted in the re-disappearance of circadian oscillation. These results demonstrate that an intrinsic program controls the formation of the circadian oscillator during the differentiation process of ES cells in vitro. The cellular differentiation and reprogramming system using cultured ES cells allows us to observe the circadian clock formation process and may help design new strategies to understand the key mechanisms responsible for the organization of the molecular oscillator in mammals.