Functional Characterisation of the Conserved FOXJ1 Effector CFAP206 in Mouse and Xenopus

纤毛功能受损导致越来越多的人类疾病，统称为纤毛病。原发性纤毛运动障碍（PCD）是一种独特的纤毛病，是由纤毛细胞器组装和功能所需的基因突变引起的无功能运动性纤毛引起的。在PCD患者中只有一小部分基因突变是已知的。在脊椎动物中，转录因子Foxj1是许多细胞类型中活动纤毛形成的关键调节因子。因此，FOXJ1调控的基因可能对运动纤毛的形成和/或功能很重要，是PCD中受影响基因的良好候选基因。我们分离到了新的Foxj1靶基因，该基因在小鼠和青蛙胚胎发生过程中选择性地活跃于纤毛细胞和组织。其中一个基因，Cfap206，编码一种功能未知的蛋白质，这种蛋白质定位于基础体，特别是一种被称为根茎的纤毛附属物。在小鼠中，Cfap206的靶向突变会在一些具有运动纤毛的组织中引起与pcd相关的表型，即精子功能受损和脑积水。在变形爪蟾蝌蚪中也观察到后一种表型，以及胚胎肾脏、肾原和幼虫表皮的纤毛粘膜上皮的表型，表明这些组织中的运动纤毛出现了故障。基于我们广泛的初步数据，我们假设Cfap206在纤毛基小体/根中发挥关键作用，调节Foxj1下游的运动和协调细胞外液流动。为了确定Cfap206的功能，我们计划综合分析Cfap206在体内PCD靶组织（精子、室管膜、黏毛上皮）中的生理和细胞功能。为了研究Cfap206的生化特性和功能，我们计划鉴定相互作用伙伴并分析它们对Cfap206功能的意义。为了实现这些目标，我们将结合先进的发育，分子，细胞和生化方法在体内和体外的小鼠和青蛙胚胎。这种互补方法在两个物种中的结果，都代表了PCD/纤毛病研究的有效模式生物，可以预期为运动性纤毛的组织特异性需求，特别是根茎功能和精子运动性提供重要的新见解。

Impaired cilia functions account for a growing list of human diseases, collectively referred to as ciliopathies. Primary ciliary dyskinesia (PCD) is a distinct group of ciliopathies specifically caused by non-functional motile cilia due to mutations in genes required for the assembly and function of these organelles. Only a subset of genes mutated in PCD patients is known. In vertebrates the transcription factor Foxj1 is a key regulator of the formation of motile cilia in numerous cell types. Thus, genes regulated by FOXJ1 are likely to be important for the formation and/or function of motile cilia and good candidates for genes affected in PCD.We have isolated novel Foxj1 target genes which are selectively active in ciliated cells and tissues during mouse and frog embryogenesis. One such gene, Cfap206, encodes a protein of unknown function that localizes to the basal body, specifically to a poorly characterized ciliary appendage called the rootlet. A targeted mutation of Cfap206 in mice causes PCD-related phenotypes in some tissues with motile cilia, i.e. impaired sperm function and hydrocephalus. The latter phenotype was also observed in morphant Xenopus tadpoles, along with phenotypes of the embryonic kidney, the pronephros, and the mucociliary epithelium of the larval epidermis, indicating malfunctioning motile cilia in these tissues. Based on our extensive preliminary data, we hypothesize that Cfap206 plays a pivotal role at the ciliary basal body/rootlet to regulate motility and coordinated extracellular fluid flow downstream of Foxj1.To determine the function of Cfap206 we plan to comprehensively analyse the physiological and cellular functions of Cfap206 in vivo in PCD target tissues (sperm, ependyma, mucociliary epithelia). To study the biochemical properties and functions of Cfap206 we plan to identify interaction partners and analyse their significance for Cfap206 function. To achieve these goals, we will combine advanced developmental, molecular, cellular and biochemical approaches in mouse and frog embryos in vivo and in vitro. The results of this complementary approach in two species, both of which represent valid model organisms for the study of PCD/ciliopathies, can be expected to provide important new insights into the tissue-specific requirements for motile cilia, particularly rootlet function and sperm motility.