COBRE: AMR: WNT SIGNALING & RETINAL REGULATION OF CIRCADIAN RHYTHMICITY

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。经典途径中Wnt信号的缺失被证明能够抑制一系列靶基因，其中一些被认为能够诱导或抑制前脑、中脑和后脑边界(MHB)、后脑和眼睛的形成。大脑和眼睛(特别是视网膜)被认为是自主的昼夜节律振荡器，许多关键的生物钟基因在斑马鱼(Danio Rerio)的大脑和眼睛中以强健的方式有节奏地表达。然而，关于Wnt信号如何调节昼夜节律性，以及可能控制生物钟基因每日振荡的可能的Wnt信号靶基因，人们知之甚少。主盲(MBL)是由乙基亚硝脲(ENU)诱导的斑马鱼大规模诱变突变。纯合主盲(MBL)突变的斑马鱼胚胎表现为眼睛和端脑减少或缺失，间脑命运扩展到脑的前部。斑马鱼axin1的GSK3结合域的突变导致了盲目MBL表型。Axin1是Wnt信号通路中的一种支架蛋白。在正常发育过程中，Axin1和未知的Wnt靶基因的抑制似乎确保了眼睛的形成。在这项拟议的研究中，我们计划确定MBL是否扰乱视网膜中昼夜节律基因的正常振荡，并利用微阵列识别可能控制昼夜节律调节的Wnt靶基因。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The absence of the Wnt signaling in the canonical pathway is shown to de-repress a cascade of target genes, some of which are implicated to be able to induce or suppress the formation of the forebrain, the midbrain and hindbrain boundary (MHB), the hindbrain, and eyes. Both the brain and eyes (particularly the retinas) are believed to be autonomous circadian oscillators and many key circadian clock genes are rhythmically expressed in the brain and eyes in a robust fashion in zebrafish (Danio rerio). Yet, little is known about how the Wnt signaling regulates circadian rhythmicity and the presumable Wnt signaling target genes that may control daily oscillations of the circadian clock genes. masterblind (mbl) is an ethyl nitrosourea (ENU)-induced mutant generated in a large-scale zebrafish mutagenesis. Zebrafish embryos homozygous for the masterblind (mbl) mutation exhibit reduced or absent eyes and telencephalon, and the expansion of the diencephalic fates to the front of the brain. A mutation in the GSK3-binding domain of zebrafish axin1, a scaffolding protein in the Wnt signaling pathway, results in the eyeless mbl phenotype. It appears that the repression of axin1 and therefore unknown Wnt target genes during the normal development secures the eye formation. In this proposed study, we plan to determine whether mbl disrupts the normal oscillations of circadian clock genes in the retinas and to identify the presumable Wnt target genes that may controls the circadian regulation using microarrays.