Developmental regulation of oscillatory expression

项目摘要 本补编用于购买关键设备，以实现 家长助学金。家长助学金项目摘要如下。 超传统振荡电路普遍存在于生物系统中。这些动态振荡器的范围从脉冲式 照射后P53的表达，对NFkB转录因子的周期性核质穿梭 干细胞和早泄患者对细胞因子、Hes/Her转录因子循环表达的反应 中胚层(PSM)。超传统的遗传振荡器与模式和发育转变有关- 振荡与酵母代谢周期相关，预示着拟南芥周期性的侧根分支， 调节幼虫的蜕皮周期，与干细胞的多能性相关，并同步转录 网柄网柄藻对饥饿信号的反应。一种生物振荡器是脊椎动物分段时钟， 它控制着体细胞发生，通过这个过程，PSM被顺序地分为称为 紧身衣。在分段时钟的核心是涉及HER/HES的自动抑制负反馈环路 转录抑制因子，进而调节额外的“循环基因”的振荡表达。虽然 人和小鼠的周期基因属于相似的通路(如Notch、Wnt、Fgf、Yap/Hippo)， 这些循环表达的途径因物种而异，Her/Hes基因家族基因是 在脊椎动物中很常见。我们研究了斑马鱼的分段时钟，它以30分钟的时间振荡 周期性的，比小鼠或人快4-12倍。为了让快速的自抑制振荡器 操作时，必须严格控制循环基因转录物和蛋白质的合成和衰退。最近 在人和小鼠之间的Hes7基因座交换实验中，体外PSM系统显示 由宿主细胞环境中的因素控制的表达延迟和衰退是关键的调控因素 时钟的参数。为了理解调节这些关键参数的机制，我们使用 斑马鱼pnrc2突变体，其转录振荡正常发生，但转录后衰退 机制被打乱，以识别额外的循环基因并剖析它们的调控。的具体目标 这些建议是为了(1)确定Pnrc2调节斑马鱼胚胎周期基因 发展作用，(2)表征调节特征和控制快速衰变动态的因素 以及(3)研究其他转录后机制在调控中的作用 分段时钟功能。我们预计，我们的工作将广泛影响对后 在许多发育环境中调节振荡表达的转录机制。

Project Summary This supplement is requested to purchase a critical piece of equipment required to achieve the aims of the parent grant. The parent grant project summary is below. Ultradian oscillatory circuits are pervasive in biological systems. These dynamic oscillators range from pulsatile p53 expression after -radiation, to periodic nuclear to cytoplasmic shuttling of NFkB transcription factor in response to cytokine, to cyclic expression of Hes/Her transcription factors in stem cells and presomitic mesoderm (PSM). Ultradian genetic oscillators are associated with patterning and developmental transitions – oscillations correlate with yeast metabolic cycles, foreshadow periodic lateral root branching in Arabidopsis, regulate molt cycles in larval worms, associate with stem cell pluripotency, and synchronize transcriptional response to starvation signals in Dictostelium. One biological oscillator is the vertebrate segmentation clock, which controls somitogenesis, the process by which the PSM is sequentially divided into segments called somites. At the core of the segmentation clock is an auto-inhibitory negative feedback loop involving Her/Hes transcriptional repressors, which in turn regulates oscillatory expression of additional ‘cyclic genes’. Although the cyclic genes in human and mouse belong to similar pathways (e.g., Notch, Wnt, FGF, Yap/Hippo), genes in those pathways which are cyclically expressed vary among species, with the Her/Hes gene family genes being common among vertebrates. We study the zebrafish segmentation clock, which oscillates with a 30-minute periodicity and is 4-12 times faster than in mouse or human. In order for a rapid auto-inhibitory oscillator to operate, there must be tight control over synthesis and decay of cyclic gene transcript and protein. A recent experiment in which the Hes7 locus was swapped between human and mouse in vitro PSM systems showed that expression delays and decay, controlled by factors in the host cell environment, are critical regulatory parameters of the clock. To understand the mechanisms regulating these critical parameters, we are using the zebrafish pnrc2 mutant in which transcriptional oscillations occur normally, but post-transcriptional decay mechanisms are disrupted, to identify additional cyclic genes and dissect their regulation. The specific aims of the proposal are to (1) identify Pnrc2-regulated zebrafish embryonic cyclic genes that play critical developmental roles, (2) characterize the regulatory features and factors that control rapid decay dynamics of cyclic gene transcripts, and (3) investigate the role of other post-transcriptional mechanism in regulating segmentation clock function. We anticipate that our work will broadly impact understanding of post- transcriptional mechanisms regulating oscillatory expression in many developmental contexts.