Transcription factors involved in retinogenesis are co-opted by the circadian clock following photoreceptor differentiation

The circadian clock is known to regulate a wide range of physiological and cellular processes, yet remarkably little is known about its role during embryo development. Zebrafish offer a unique opportunity to explore this issue, not only because a great deal is known about key developmental events in this species, but also because the clock starts on the very first day of development. In this study, we identified numerous rhythmic genes in zebrafish larvae, including the key transcriptional regulators neurod and cdx1b, which are involved in neuronal and intestinal differentiation, respectively. Rhythmic expression of neurod and several additional transcription factors was only observed in the developing retina. Surprisingly, these rhythms in expression commenced at a stage of development after these transcription factors are known to have played their essential role in photoreceptor differentiation. Furthermore, this circadian regulation was maintained in adult retina. Thus, once mature ...

昼夜节律钟（circadian clock）已知调控广泛的生理和细胞过程，但关于其在胚胎发育中的作用却知之甚少。斑马鱼为探索这一问题提供了独特的机会，不仅因为该物种的关键发育事件已被深入研究，还因为其节律钟在发育的第一天就开始运作。本研究在斑马鱼幼体中鉴定出大量节律基因，包括关键转录调控因子neurod和cdx1b，它们分别参与神经元和肠道分化。neurod及其他几个转录因子的节律性表达仅在发育中的视网膜中被观察到。令人惊讶的是，这些表达节律开始于这些转录因子已知在光感受器分化中发挥关键作用之后的发育阶段。此外，这种昼夜节律调控在成年视网膜中得以维持。因此，一旦成熟...