Genetic Analysis of the Zebrafish Somitogenesis Oscillator

振荡在生物学中是常见的，例如生物钟、心脏起搏器、皮质节律，并且已经在细胞信号网络中观察到作为反馈回路的结果。这些细胞和生理节律维持体内平衡，并且这些节律的分析是生物医学科学中的新兴领域。在脊椎动物的分割过程中，超日振荡支配着体节的形成，体节是脊柱的分割原基。在斑马鱼、小鼠和人类中，体节发生需要Notch信号，其扰动导致畸形椎骨，这是一种称为脊椎肋骨发育不全的出生缺陷。Notch依赖性抑制导致斑马鱼的分节组织中的细胞经历Notch靶基因的表达和抑制的重复循环。HER（hairy/enhancer of split related transFiftional repressors）基因被认为在斑马鱼的分段时钟内形成负反馈环。目前的数据表明，不同的基因具有独特的和冗余的功能。目的我是为了了解她的基因在斑马鱼的时钟功能的多样化，并确定顺式序列控制转录振荡。为了实现这些目标，我们将使用电泳迁移率变动分析（EMSA），免疫沉淀和转基因斑马鱼。目的二是开发一种温度敏感的控制转基因，以精确地调整表达的水平和时间。这一策略涉及在动态信号网络和发育时间的背景下识别信号整合和基因功能的一般问题。目的III是描述细胞运动和分割时钟之间的关系。使用时间推移成像和细胞跟踪，我们将确定速度。尾芽不同部位细胞的方向和相邻关系。

Oscillations are common in biology, e.g. the circadian clock, cardiac pacemaker, cortical rhythms, and have been observed in cell signaling networks as a result of feedback loops. These cellular and physiological oscilla tions maintain homeostasis and analysis of these rhythms is an emerging area in biomedical science. During vertebrate segmentation, ultradian oscillations govern the formation of somites, the segmented anlagen of the vertebral column. In zebrafish, mice and humans, somitogenesis requires Notch signaling, perturbation of which leads to malformed vertebrae, a birth defect called spondylocostal dysostosis. The Notchdependent oscilla tions cause cells in the segmenting tissue of the zebrafish to undergo repeated cycles of expression and repression of Notch target genes. The her (hairy/enhancer of split related tranSCfiptional repressors) genes are thought to form a negative feedback loop within the zebrafish segmentation clock. Current data suggest thai the different /lergenes have both unique and redundant functions. Aim I is to understand the functional diversification of her genes within the zebrafish clock and to identify cis sequences that govern transcriptional oscillations. To achieve these aims, we will use electrophoretic mobility shift assays (EMSA), immunoprecipitation and transgenic zebrafish. Aim II is to develop a temperature-sensitive control of the transgenes in order to precisely tune the level and timing of expression. This strategy deals with the general problem of discerning signal integration and gene function within the context of dynamic signaling networks and developmental lime. We are Aim III is to characterize the relationship between cell movement and the segmentation clock. Using timelapse imaging and celt tracking, we will determine the velocity. direction and neighbor relationships of celts in different rQ9ions of the tail bud.