Investigating the role of MeCP2 in activity-dependent gene expression

描述（由申请人提供）：Rett综合征（RTT）是一种X连锁进行性神经发育障碍，是女孩严重智力残疾和自闭症样症状的常见原因。MECP 2（一种甲基CpG结合蛋白）的突变是大多数RTT病例的原因。MeCP 2是一种甲基CpG结合蛋白，通过结合NCoR/HDAC 3组蛋白脱乙酰酶复合物抑制转录。精氨酸306突变为胞嘧啶（R306 C）导致RTT并破坏MeCP 2与NCoR复合物的结合，表明MeCP 2-NCoR相互作用对大脑发育至关重要，破坏该复合物导致RTT。格林伯格实验室在其对神经元活性依赖性基因转录的研究中发现，响应于感觉体验，MeCP 2在苏氨酸308（T308）处磷酸化，并且这种磷酸化事件干扰NCoR与MeCP 2的相互作用。此外，初步实验表明MeCP 2 T308突变为丙氨酸（T308 A）导致活性调节基因Npas 4的诱导减弱。Npas 4基因编码一种转录因子，控制兴奋性神经元上抑制性突触的形成。因此，我们的初步数据表明MeCP 2和NCoR之间的相互作用可能对Npas 4表达至关重要，并且在RTT中被错误调节。为了验证这一假设，我们提出了以下具体目标：（1）进一步研究MeCP 2-NCoR复合物是否调节神经元活性依赖性基因表达和（2）确定MeCP 2-NCoR复合物是否通过与Npas 4基因的调节区以活性依赖性方式结合来调节基因表达。我们希望，这些拟议的实验将提供一个更好的了解MeCP 2的功能，并将建议潜在的治疗策略，治疗RTT。

DESCRIPTION (provided by applicant): Rett Syndrome (RTT) is an X-linked progressive neurodevelopmental disorder and is a common cause of severe intellectual disability and autistic-like symptoms in girls. Mutations in MECP2, a methyl-CpG-binding protein, cause of the majority of RTT cases. MeCP2 is a methyl-CpG-binding protein that represses transcription by binding the NCoR/HDAC3 histone deacetylase complex. Mutation of arginine 306 to cytosine (R306C) causes RTT and disrupts binding of MeCP2 to the NCoR complex, suggesting that MeCP2-NCoR interaction is critical for brain development and that disrupting this complex leads to RTT. The Greenberg laboratory, in its studies of neuronal activity-dependent gene transcription, discovered that in response to sensory experience MeCP2 becomes phosphorylated at threonine 308 (T308) and that this phosphorylation event perturbs the interaction of NCoR with MeCP2. Furthermore, preliminary experiments suggest that mutation of MeCP2 T308 to alanine (T308A) leads to attenuation of the induction of the activity-regulated gene Npas4. The Npas4 gene encodes a transcription factor that controls inhibitory synapse formation onto excitatory neurons. Thus, our preliminary data suggest that the interaction between MeCP2 and NCoR may be critical for Npas4 expression and is misregulated in RTT. To test this hypothesis we propose the following specific aims: (1) to further investigate if MeCP2-NCoR complex regulates neuronal activity-dependent gene expression and (2) to determine if the MeCP2-NCoR complex regulates gene expression by associating with the regulatory region of the Npas4 gene in an activity-dependent manner. It is our hope that these proposed experiments will provide a better understanding of MeCP2 function and will suggest potential therapeutic strategies for treating RTT.