An optimal Golgi transport system is important for mammalian cells. The adenosine diphosphate (ADP) ribosylation factors (ARF) are key proteins for regulating cargo sorting at the Golgi network. In this family, ARF3 mainly works at the trans-Golgi network (TGN), and no ARF3-related phenotypes have yet been described in humans. We here report the clinical and genetic evaluations of two unrelated children with de novo pathogenic variants in the ARF3 gene: c.200A > T (p.Asp67Val) and c.296G > T (p.Arg99Leu). Although the affected individuals presented commonly with developmental delay, epilepsy and brain abnormalities, there were differences in severity, clinical course and brain lesions. In vitro subcellular localization assays revealed that the p.Arg99Leu mutant localized to Golgi apparatus, similar to the wild-type, whereas the p.Asp67Val mutant tended to show a disperse cytosolic pattern together with abnormally dispersed Golgi localization, similar to that observed in a known dominant negative variant (p.Thr31Asn). Pull-down assays revealed that the p.Asp67Val had a loss-of-function effect and the p.Arg99Leu variant had increased binding of the adaptor protein, Golgi-localized, γ-adaptin ear-containing, ARF-binding protein 1 (GGA1), supporting the gain of function. Furthermore, in vivo studies revealed that p.Asp67Val transfection led to lethality in flies. In contrast, flies expressing p.Arg99Leu had abnormal rough eye, as observed in the gain-of-function variant p.Gln71Leu. These data indicate that two ARF3 variants, the possibly loss-of-function p.Asp67Val and the gain-of-function p.Arg99Leu, both impair the Golgi transport system. Therefore, it may not be unreasonable that they showed different clinical features like diffuse brain atrophy (p.Asp67Val) and cerebellar hypoplasia (p.Arg99Leu).

中文翻译：

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从头 ARF3 变体导致大脑异常的神经发育障碍

最佳的高尔基体运输系统对哺乳动物细胞很重要。二磷酸腺苷 (ADP) 核糖基化因子 (ARF) 是调节高尔基网络中货物分类的关键蛋白质。在这个家族中，ARF3 主要作用于跨高尔基网络 (TGN)，尚未在人类中描述与 ARF3 相关的表型。我们在此报告了 ARF3 基因中具有新生致病性变异的两个无关儿童的临床和遗传评估：c.200A > T (p.Asp67Val) 和 c.296G > T (p.Arg99Leu)。尽管受影响的个体通常出现发育迟缓、癫痫和脑部异常，但在严重程度、临床过程和脑部病变方面存在差异。体外亚细胞定位分析显示 p.Arg99Leu 突变体定位于高尔基体，类似于野生型，而 p.Arg99Leu 突变体定位于高尔基体，类似于野生型。Asp67Val 突变体倾向于显示分散的胞质模式以及异常分散的高尔基体定位，类似于在已知的显性负变体 (p.Thr31Asn) 中观察到的情况。下拉分析显示 p.Asp67Val 具有功能丧失效应，而 p.Arg99Leu 变体增加了衔接蛋白、高尔基体定位、含 γ-适配蛋白、ARF 结合蛋白 1（GGA1 )，支持函数增益。此外，体内研究表明 p.Asp67Val 转染导致果蝇致死。相比之下，表达 p.Arg99Leu 的果蝇有异常粗糙的眼睛，如在功能增益变体 p.Gln71Leu 中观察到的。这些数据表明两种 ARF3 变体，可能功能丧失的 p.Asp67Val 和功能获得的 p.Arg99Leu，都损害高尔基体运输系统。所以，