Zfp423 Regulates Sonic Hedgehog Signaling via Primary Cilium Function.
Zfp423 Regulates Sonic Hedgehog Signaling via Primary Cilium Function.
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DOI：
10.1371/journal.pgen.1006357
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发表时间：
2016-10
期刊：
影响因子：
4.5
通讯作者：
Hamilton BA
中科院分区：
文献类型：
--
作者：
Hong CJ;Hamilton BA
Zfp423编码一个30个锌指转录因子，它与几条典型的信号通路相交。Zfp423突变导致与纤毛疾病相关的表型，包括小鼠的小脑虫发育不全，以及人类的Joubert综合征(JBTS19)和肾单位(NPHP14)。与大多数纤毛疾病基因不同，Zfp423编码一种核蛋白，其发育表达是复杂的，这导致了对细胞机制的替代建议。在这里，我们发现Zfp423是通过小脑颗粒细胞前体表达的，在这些前体中Zfp423的缺失导致细胞固有的增殖减少，对Shh的反应丧失，以及包括Smoothed和IFT88定位频率降低的初级纤毛异常。Zfp423的缺失改变了几个编码纤毛关键成分的基因的表达，包括Tulp3的表达增加。Tulp3是Zfp423的直接结合靶点，在Zfp423缺陷细胞中减少Tulp3的过表达可抑制光滑化易位缺陷。这些结果将Zfp423缺乏症定义为真正的纤毛病变，作用于Shh信号的上游，并表明导致小脑发育不良的颗粒细胞前体的内在机制。纤毛病是一组个别罕见的遗传性疾病，具有重叠的表型和构成初级纤毛成分的基因突变。ZNF423的突变是一个例外。患者和小鼠模型显示出典型的小脑中线发育不良(Joubert综合征)，但该基因编码一种核转录因子。小鼠的Zfp423基因是以动态发育模式表达的，这使得这种大脑畸形的细胞机制尚未解决。一份报告认为Shh是小脑颗粒细胞前体(GCPs)的关键有丝分裂原，其信号转导发生在初级纤毛，浦肯野细胞Shh的表达减少是关键事件。我们发现Zfp423突变体表达了正常的Shh水平，但Zfp423缺失的GCP无法对Shh做出反应。Zfp423突变的GCPs原生纤毛通常有一个更宽的基座和更长的伸展。ZNF423-人类细胞培养模型中的缺失导致Smoothens和鞭毛内运输蛋白IFT88的移位减少，Smoothens是Shh信号转导中的关键事件。RNA-Seq和RT-qPCR实验确定已知的纤毛病变基因是ZNF423和Zfp423的潜在保守靶点。其中TULP3在ZNF423/Zfp423缺陷细胞中表达上调，并在颗粒细胞前体中直接与Zfp423结合。在ZNF423缺失的人细胞培养模型中，逆转TULP3的过度表达逆转了光滑化易位的缺陷。
Zfp423 encodes a 30-zinc finger transcription factor that intersects several canonical signaling pathways. Zfp423 mutations result in ciliopathy-related phenotypes, including agenesis of the cerebellar vermis in mice and Joubert syndrome (JBTS19) and nephronophthisis (NPHP14) in humans. Unlike most ciliopathy genes, Zfp423 encodes a nuclear protein and its developmental expression is complex, leading to alternative proposals for cellular mechanisms. Here we show that Zfp423 is expressed by cerebellar granule cell precursors, that loss of Zfp423 in these precursors leads to cell-intrinsic reduction in proliferation, loss of response to Shh, and primary cilia abnormalities that include diminished frequency of both Smoothened and IFT88 localization. Loss of Zfp423 alters expression of several genes encoding key cilium components, including increased expression of Tulp3. Tulp3 is a direct binding target of Zfp423 and reducing the overexpression of Tulp3 in Zfp423-deficient cells suppresses Smoothened translocation defects. These results define Zfp423 deficiency as a bona fide ciliopathy, acting upstream of Shh signaling, and indicate a mechanism intrinsic to granule cell precursors for the resulting cerebellar hypoplasia. Ciliopathies are a broad group of individually rare genetic disorders that share overlapping phenotypes and mutations in genes that make components of the primary cilium. Mutations in ZNF423 are an exception. Patients and mouse models show characteristic hypoplasia of the cerebellar midline (Joubert syndrome), but the gene encodes a nuclear transcription factor. The mouse gene, Zfp423, is expressed in a dynamic developmental pattern, leaving the cellular mechanism for this brain malformation unresolved. One report suggested reduced Purkinje cell expression of Shh, a key mitogen for cerebellar granule cell precursors (GCPs) whose signal transduction occurs at the primary cilium, as the key event. We show that Zfp423 mutants expressed normal Shh levels, but that Zfp423-depleted GCPs were unable to respond to Shh. Primary cilia on Zfp423-mutant GCPs in situ typically had a wider base and longer extension. ZNF423-depletion in a human cell culture model resulted in diminished translocation of Smoothened, a key event in Shh signaling, and of the intraflagellar transport protein IFT88. RNA-Seq and RT-qPCR experiments identified known ciliopathy genes as potential conserved targets of ZNF423 and Zfp423. One of these, TULP3, was both up-regulated in ZNF423/Zfp423-deficient cells and directly bound by Zfp423 in granule cell precursors. Reversing the overexpression of TULP3 in ZNF423-depleted human cell culture model reversed the defect in Smoothened translocation.
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影响因子：
4.5
作者：
Concepcion D;Flores-García L;Hamilton BA
通讯作者：
Hamilton BA
影响因子：
64.5
作者：
Chaki M;Airik R;Ghosh AK;Giles RH;Chen R;Slaats GG;Wang H;Hurd TW;Zhou W;Cluckey A;Gee HY;Ramaswami G;Hong CJ;Hamilton BA;Cervenka I;Ganji RS;Bryja V;Arts HH;van Reeuwijk J;Oud MM;Letteboer SJ;Roepman R;Husson H;Ibraghimov-Beskrovnaya O;Yasunaga T;Walz G;Eley L;Sayer JA;Schermer B;Liebau MC;Benzing T;Le Corre S;Drummond I;Janssen S;Allen SJ;Natarajan S;O'Toole JF;Attanasio M;Saunier S;Antignac C;Koenekoop RK;Ren H;Lopez I;Nayir A;Stoetzel C;Dollfus H;Massoudi R;Gleeson JG;Andreoli SP;Doherty DG;Lindstrad A;Golzio C;Katsanis N;Pape L;Abboud EB;Al-Rajhi AA;Lewis RA;Omran H;Lee EY;Wang S;Sekiguchi JM;Saunders R;Johnson CA;Garner E;Vanselow K;Andersen JS;Shlomai J;Nurnberg G;Nurnberg P;Levy S;Smogorzewska A;Otto EA;Hildebrandt F
通讯作者：
Hildebrandt F
DOI：
10.1083/jcb.100.2.384
发表时间：
1985-02
期刊：
The Journal of cell biology
影响因子：
--
作者：
Hatten ME
通讯作者：
Hatten ME
影响因子：
3.5
作者：
Alcaraz, Wendy A.;Chen, Edward;Hamilton, Bruce A.
通讯作者：
Hamilton, Bruce A.
影响因子：
16.2
作者：
Gold, DA;Baek, SH;Hamilton, BA
通讯作者：
Hamilton, BA