Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA.
Endocrinology. 2011 May;152(5):1860-71. doi: 10.1210/en.2010-1183. Epub 2011 Mar 8.
Recent genome-wide association studies have implicated the clusterin gene in the etiology of Alzheimer's disease. The expression and function of clusterin in the developing brain, however, is poorly understood. In this study, we have characterized the zebrafish clusterin gene and determined its structural conservation, developmental expression, and physiological regulation. The structure of the zebrafish clusterin gene and protein is similar to its human orthologue. Biochemical assays show that zebrafish Clusterin is a secreted protein that cannot bind IGFs. In adult zebrafish, clusterin mRNA is detected in many tissues. In early development, clusterin mRNA becomes detectable at 12 h postfertilization, and its levels gradually increase thereafter. In situ hybridization analysis indicates that clusterin mRNA is specifically expressed in the developing diencephalic and myelencephalic choroid plexus. Among various stresses tested, heat shock, but not hypoxic or ionic stresses, increases the levels of clusterin mRNA. Inhibition of the IGF-I receptor-mediated signaling or overexpression of IGF ligands did not change clusterin mRNA levels. In comparison, inhibition or targeted knockdown of Notch signaling significantly increased clusterin mRNA expression in choroid plexus. These results suggest that clusterin is a marker of choroid plexus in zebrafish, and its expression in the developing choroid plexus is under the regulation of Notch but not IGF signaling.
最近的全基因组关联研究表明，簇蛋白基因与阿尔茨海默病的病因有关。然而，簇蛋白在发育中的大脑中的表达和功能还知之甚少。在这项研究中，我们对斑马鱼簇蛋白基因进行了特征描述，并确定了其结构保守性、发育表达和生理调节。斑马鱼簇蛋白基因和蛋白质的结构与其人类同源物相似。生化分析表明，斑马鱼 Clusterin 是一种分泌蛋白，不能结合 IGFs。在成年斑马鱼中，clusterin mRNA 可在许多组织中检测到。在早期发育中，clusterin mRNA 在受精后 12 小时即可检测到，此后其水平逐渐增加。原位杂交分析表明，clusterin mRNA 特异性表达于发育中的间脑和延髓脉络丛。在测试的各种应激中，热应激而非低氧或离子应激会增加 clusterin mRNA 的水平。IGF-I 受体介导的信号转导的抑制或 IGF 配体的过表达并没有改变 clusterin mRNA 水平。相比之下，Notch 信号转导的抑制或靶向敲低显著增加了脉络丛中 clusterin mRNA 的表达。这些结果表明，clusterin 是斑马鱼脉络丛的标志物，其在发育中的脉络丛中的表达受 Notch 而不是 IGF 信号的调节。
