Characterization of MeCP2 target genes in Rett Syndrome

描述（由申请人提供）：D。甲基化CpG结合蛋白2（Mecp 2/MECP 2）被认为选择性地结合哺乳动物基因组中的甲基化CpG二核苷酸，并且通过与SinSA相互作用和募集组蛋白脱乙酰酶（HSP 70）而在体内起转录抑制剂的作用。MECP 2的突变与Rett综合征有关，Rett综合征是一种X连锁神经发育障碍。我们最近发现，母系表达的印记基因，Dlx 5，是一个直接的目标基因Mecp 2在小鼠大脑和淋巴母细胞从Rett综合征的个人。DLX 5显示印迹丧失。结果，当Mecp 2不存在或突变时，Dlx 5表达增加2倍。我们还报道了Mecp 2通过在转录沉默的染色质中特异性地形成染色质环来调节基因。DLX 5调节β-氨基丁酸（GABA）的产生。使用表达增加的DLX 5水平的转基因小鼠，我们建议研究Dlx 5/DLX 5失调本身是否足以引起Rett综合征的一些神经表型。我们将通过对DLX 5转基因小鼠的系统行为分析来研究这个问题。我们将研究Dlx 5和Gad（一种合成GABA的酶）以及GABA本身在野生型、Mecp 2-null和DLX 5转基因小鼠脑的各个亚区中的表达（具体目标1和2）。除了Dlx 5之外，我们最近还发现了另一个印记基因Peg 3，它在Mecp 2缺失的大脑海马体中失调。我们将研究Peg 3是否也是Mecp 2的直接靶基因，如果是，我们将确定Mecp 2如何调节该基因的表达（特异性目的3）。由于已知Peg 3与母性行为有关，我们将评估Mecp 2（+/-）雌性小鼠的母性行为，这些小鼠的大脑中表达了增加水平的Peg 3。此外，我们将通过体外分化细胞培养系统评估Peg 3在肌生成中的过表达（特异性目的4）。这是因为Peg 3在成年小鼠的大脑和骨骼肌中特异性且大量表达。我们的研究将提供有关Mecp 2活性的分子机制以及MECP 2突变如何导致Rett综合征的信息。

DESCRIPTION (provided by applicant): D. Methyl-CpG binding protein 2 (Mecp2/MECP2) is thought to selectively bind methyl-CpG dinucleotides in the mammalian genome and to function as a transcriptional represser in vivo by interacting with SinSA and recruiting histone deaceylase (Hdac). Mutations in MECP2 are associated with Rett syndrome, an X-linked neurodevelopmental disorder. We recently found that a maternally expressed imprinted gene, Dlx5, is a direct target gene for Mecp2 in mouse brain and in lympholastoid cells from individuals with Rett syndrome. DLX5 showed a loss of imprinting. As a result, Dlx5 expression is increased 2-fold when Mecp2 is absent or mutated. We also reported that Mecp2 regulates genes by forming a chromatin loop specifically in transcriptionally silent chromatin. DLX5 regulates the production of (-aminobutyric acid (GABA). Using transgenic mice expressing increased levels of DLX5, we propose to study whether Dlx5/DLX5 dysregulation per se is sufficient to cause some of the neurological phenotypes of Rett syndrome. We will investigate this question by systematic behavioral analyses of the DLX5 transgenic mice. We will study expression of Dlx5 and Gad, an enzyme which synthesizes GABA, as well as GABA itself, in various subregions of the brains of wild-type, Mecp2-null, and DLX5 transgenic mice (Specific Aim 1 and 2). In addition to Dlx5, we recently identified another imprinted gene, Peg3, to be dysregulated in the hippocampus of the Mecp2-null brain. We will study whether Peg3 is also a direct target gene for Mecp2, and if it is, we will determine how Mecp2 regulates expression of this gene (Specific Aim 3). Because Peg3 is known to be linked to maternal behaviors, we will evaluate the maternal behaviors of Mecp2 (+/-) female mice expressing increased levels of Peg3 in their brain. Furthermore, we will evaluate Peg3 overexpression in myogenesis by the in vitro differentiation cell culture system (Specific Aim 4). This is because Peg3 is specifically and abundantly expressed in the brain and skeletal muscle in adult mice. Our study will provide information about the molecular mechanisms underlying Mecp2 activity and how MECP2 mutations might cause Rett syndrome.