Human mutations in integrator complex subunits link transcriptome integrity to brain development.
Human mutations in integrator complex subunits link transcriptome integrity to brain development.
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DOI：
10.1371/journal.pgen.1006809
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发表时间：
2017-05
期刊：
影响因子：
4.5
通讯作者：
Mancini GMS
中科院分区：
文献类型：
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作者：
Oegema R;Baillat D;Schot R;van Unen LM;Brooks A;Kia SK;Hoogeboom AJM;Xia Z;Li W;Cesaroni M;Lequin MH;van Slegtenhorst M;Dobyns WB;de Coo IFM;Verheijen FW;Kremer A;van der Spek PJ;Heijsman D;Wagner EJ;Fornerod M;Mancini GMS
整合子是一种RNA聚合酶II（RNAPII）相关复合物，最近被发现在RNA加工和转录调节中具有广泛作用。重要的是，它在人类发育和疾病中的作用迄今为止在很大程度上尚未探索。在这里，我们提供的证据表明，双等位基因整合子复合物亚基1（INTS 1）和亚基8（INTS 8）基因突变与罕见的隐性人类神经发育综合征。三个不相关的荷兰血统的个人表现出相同的纯合子截短INTS 1突变。三个兄弟姐妹携带复合杂合子INTS8突变。这六个人的共同特征是严重的神经发育迟缓和独特的外观。此外，INTS 8家族还表现出神经元迁移缺陷（室周结节性异位）。我们发现，第一个INTS8突变，一个9个碱基对的缺失，导致破坏INT复合物稳定性的蛋白质，而第二个错义突变引入了一个选择性剪接位点，导致不稳定的信使。来自具有INTS 8突变的患者的细胞显示出未加工的UsnRNA的水平增加，与UsnRNA的3 '端成熟中的INT功能相容，并且显示出基因表达和RNA加工的显著破坏。最后，使用基因组编辑在P19细胞中引入INTS 8缺失突变改变了整个维甲酸诱导的神经分化过程中的基因表达。总之，我们的研究结果证实了整合子对转录组完整性的重要作用，并指出了整合子复合物在人脑发育中的需求。神经发育障碍通常有遗传原因，但涉及的基因和潜在机制越来越多样化，这表明大脑发育的复杂性。对于正常的细胞功能和一般的正常发育，调节基因转录成mRNA的机制至关重要，因为关键发育调节转录物的适当空间和时间表达至关重要。整合子复合物最近被鉴定为在RNA加工和转录调节中具有广泛的作用。这种复合物由至少14种不同的亚基组装而成，一些动物研究已经指出了它在发育中的重要作用。然而，到目前为止，还没有直接证明这种复合物与人类健康和发展相关的研究。我们在这里表明，在整合子复合物亚基1基因（INTS 1）和亚基8基因（INTS 8）的突变导致严重的神经发育综合征，其特征是严重的智力残疾，癫痫，痉挛，面部和肢体畸形和微妙的结构性脑异常。虽然最近已经确定了整合剂复合物在神经元迁移中的作用，但我们提供的证据表明，INTS 8突变在体外导致复合物的不稳定性和功能受损。在患者培养的成纤维细胞中，我们发现mRNA转录和加工异常的证据。此外，在维甲酸诱导的神经元分化的体外模型中引入INTS 8突变也导致转录改变。总之，我们的研究结果表明，INTS1和INTS8在大脑发育中的进化保守的要求。
Integrator is an RNA polymerase II (RNAPII)-associated complex that was recently identified to have a broad role in both RNA processing and transcription regulation. Importantly, its role in human development and disease is so far largely unexplored. Here, we provide evidence that biallelic Integrator Complex Subunit 1 (INTS1) and Subunit 8 (INTS8) gene mutations are associated with rare recessive human neurodevelopmental syndromes. Three unrelated individuals of Dutch ancestry showed the same homozygous truncating INTS1 mutation. Three siblings harboured compound heterozygous INTS8 mutations. Shared features by these six individuals are severe neurodevelopmental delay and a distinctive appearance. The INTS8 family in addition presented with neuronal migration defects (periventricular nodular heterotopia). We show that the first INTS8 mutation, a nine base-pair deletion, leads to a protein that disrupts INT complex stability, while the second missense mutation introduces an alternative splice site leading to an unstable messenger. Cells from patients with INTS8 mutations show increased levels of unprocessed UsnRNA, compatible with the INT function in the 3’-end maturation of UsnRNA, and display significant disruptions in gene expression and RNA processing. Finally, the introduction of the INTS8 deletion mutation in P19 cells using genome editing alters gene expression throughout the course of retinoic acid-induced neural differentiation. Altogether, our results confirm the essential role of Integrator to transcriptome integrity and point to the requirement of the Integrator complex in human brain development. Neurodevelopmental disorders often have a genetic cause, however the genes and the underlying mechanisms that are involved are increasingly diverse, pointing to the complexity of brain development. For normal cell function and in general for normal development, mechanisms that regulate gene transcription into mRNA are of outermost importance as proper spatial and temporal expression of key developmentally regulated transcripts is essential. The Integrator complex was recently identified to have a broad role in both RNA processing and transcription regulation. This complex is assembled from at least 14 different subunits and several animal studies have pointed to an important role in development. Nevertheless, studies directly demonstrating the relevance of this complex in human health and development have been lacking until now. We show here that mutations in the Integrator Complex Subunit 1 gene (INTS1) and Subunit 8 gene (INTS8) cause a severe neurodevelopmental syndrome, characterized by profound intellectual disability, epilepsy, spasticity, facial and limb dysmorphism and subtle structural brain abnormalities. While the role of the Integrator complex in neuronal migration has recently been established, we provide evidence that INTS8 mutations lead in vitro to instability of the complex and impaired function. In patients cultured fibroblasts we found evidence for abnormalities in mRNA transcription and processing. In addition, introduction of INTS8 mutations in an in vitro model of retinoic acid-induced neuronal differentiation results also in transcription alterations. Altogether our results suggest an evolutionary conserved requirement of INTS1 and INTS8 in brain development.