Genetic Analysis of the Zebrafish Somitogenesis Oscillator

振荡在生物学中很常见，例如生物钟、心脏起搏器、皮质节律，并且在细胞信号网络中作为反馈回路的结果被观察到。这些细胞和生理振荡维持了体内平衡，对这些节律的分析是生物医学科学的一个新兴领域。在脊椎动物分割过程中，超声振荡控制着体的形成，体是脊柱的分割性胶原。在斑马鱼、老鼠和人类中，体细胞的发生需要Notch信号，这种信号的干扰会导致脊椎畸形，一种被称为脊柱脊柱发育不良的先天缺陷。Notch依赖性振荡导致斑马鱼切割组织中的细胞经历Notch靶基因的表达和抑制的重复循环。她（分裂相关转录抑制因子的毛状/增强子）基因被认为在斑马鱼分割时钟内形成负反馈回路。目前的数据表明，不同的基因既有独特的功能，也有冗余的功能。目的一是了解她的基因在斑马鱼时钟内的功能多样化，并确定控制转录振荡的顺式序列。为了实现这些目标，我们将使用电泳迁移位移测定（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转基因控制，以精确调节表达的水平和时间。该策略解决了在动态信号网络和发育过程中识别信号整合和基因功能的一般问题。我们的目标III是描述细胞运动和分割时钟之间的关系。使用延时成像和细胞跟踪，我们将确定速度。尾芽不同部位细胞的方向及邻近关系。

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.