Neuron-specific impairment of inter-chromosomal pairing and transcription in a novel model of human 15q-duplication syndrome
Neuron-specific impairment of inter-chromosomal pairing and transcription in a novel model of human 15q-duplication syndrome
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DOI：
10.1093/hmg/ddr298
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发表时间：
2011-10-01
影响因子：
3.5
通讯作者：
Horike, Shin-ichi
中科院分区：
文献类型：
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作者：
Meguro-Horike, Makiko;Yasui, Dag H.;Horike, Shin-ichi
虽然自闭症的病因在很大程度上仍不清楚，但细胞遗传学和遗传学研究表明，在1-3%的自闭症病例中，母亲的拷贝数增加了15q11-q13。为了了解母体15q复制如何导致基因表达失调和染色质相互作用改变，我们使用微细胞介导的染色体转移在人类神经细胞系中建立了一种新的母体15q复制模型。我们的15q重复神经元模型显示，通过定量RT-PCR，NDN、Snrpn、GABRB3和CHRNA7的转录水平与预期水平相比降低，尽管启动子DNA甲基化没有检测到变化。由于15q11-q13等位基因已被证明在成熟的人类神经元中表现出同源配对，我们用荧光原位杂交的方法评估了15q11-q13的同源配对。15q重复显著破坏了15q11-q13的同源配对。为了进一步了解15q11-q13同源配对的范围和机制，我们将同源配对的最小区域定位在GABRB3的3‘端一个类似500kb的区域，该区域包含多个染色质调节因子MeCP2和CTCF的结合位点。在神经元成熟分化过程中，15q11-q13的同源配对需要活跃的转录和染色质因子MeCP2和CTCF。这些数据支持这样一种模型，即15q11-q13基因在染色体间和染色体内的联合水平上受表观遗传调控，而染色体不平衡扰乱了15q11-q13基因的表观遗传调控。
Although the etiology of autism remains largely unknown, cytogenetic and genetic studies have implicated maternal copy number gains of 15q11-q13 in 1-3% of autism cases. In order to understand how maternal 15q duplication leads to dysregulation of gene expression and altered chromatin interactions, we used microcell- mediated chromosome transfer to generate a novel maternal 15q duplication model in a human neuronal cell line. Our 15q duplication neuronal model revealed that by quantitative RT-PCR, transcript levels of NDN, SNRPN, GABRB3 and CHRNA7 were reduced compared with expected levels despite having no detectable alteration in promoter DNA methylation. Since 15q11-q13 alleles have been previously shown to exhibit homologous pairing in mature human neurons, we assessed homologous pairing of 15q11-q13 by fluorescence in situ hybridization. Homologous pairing of 15q11-q13 was significantly disrupted by 15q duplication. To further understand the extent and mechanism of 15q11-q13 homologous pairing, we mapped the minimal region of homologous pairing to a similar to 500 kb region at the 3' end of GABRB3 which contains multiple binding sites for chromatin regulators MeCP2 and CTCF. Both active transcription and the chromatin factors MeCP2 and CTCF are required for the homologous pairing of 15q11-q13 during neuronal maturational differentiation. These data support a model where 15q11-q13 genes are regulated epigenetically at the level of both inter-and intra-chromosomal associations and that chromosome imbalance disrupts the epigenetic regulation of genes in 15q11-q13.