Role of H2A.z isoforms in neuronal transcription and synaptic plasticity.

关于表观遗传过程在维持或放松心理健康方面的作用，人们知之甚少。 了解这些表观遗传过程是至关重要的，因为 大脑的许多发育和精神障碍，如自闭症谱系障碍（ASD）， 正在以惊人的速度上升，现在是主要的公共卫生问题。最近，两个密切相关的 已经报道了H2A.Z超变体（H2A.z1和H2A.z2），其彼此仅相差三个 个氨基酸尽管有这些细微的差异，使用微阵列的初步数据表明， 这些超变异体在神经元基因转录中的独立作用。在大约1000名 受H2A.z1或H2A.z2敲低影响的基因，少于5%受缺乏任一同种型影响， 这强烈表明这些亚型在神经元基因调控中的功能在很大程度上不重叠。一 这种受H2A.z同种型强烈调节基因是homer 1，已知当突变时， 精神分裂症和自闭症的危险因素初步数据显示，短的可诱导的homer 1的mRNA水平， 同种型homer 1a在H2A.z1耗尽后减少，但在H2A.z2同样耗尽时增加。 有趣的是，微阵列数据的基因本体分析揭示了几个对H2A.z1敏感的基因， 而不是H2A.z2，缺失是已知的ASD和精神分裂症候选基因，指示可能的 H2A.Z在这些脑疾病的病因学中的高变特异性作用。因此，本提案旨在 在神经元功能和突触可塑性的背景下研究这些超变异体。三个具体目标是 提出了首先，将研究H2A.Z超变体在快速活性诱导的诱导中的作用。 homer 1a使用RNA和染色质免疫沉淀技术。第二，两者的DNA结合位点 整个基因组中的H2A.Z亚型及其在神经元活动依赖性和非依赖性中的作用 将通过对来自H2A.z1-或H2A.z2-缺失的DNA和RNA进行深度测序来研究转录 神经元第三，将研究H2 A. Z超变体在突触和非突触神经元功能中的作用 通过电生理和钙成像技术。

Very little is known about the role of epigenetic processes in maintenance or deregulation of mental health. Understanding these epigenetic processes is of paramount importance in light of the fact that incidence of many developmental and psychiatric disorders of the brain, such as the Autism Spectrum Disorders (ASDs), are on the rise at an alarming rate and are now major public health concerns. Recently two closely related H2A.Z hypervariants (H2A.z1 and H2A.z2) have been reported that differ from each other by only three amino acids. Despite such subtle differences, preliminary data using microarrays suggest largely independent roles of these hypervariants in neuronal gene transcription. Among the approximately 1000 genes affected by H2A.z1 or H2A.z2 knockdown, less than 5% were affected by lack of either isoform, strongly suggesting largely non-overlapping functions of these isoforms in neuronal gene regulation. One such gene, strongly regulated by H2A.z isoforms, is homerl, which, when mutated, is known to be a risk factor for schizophrenia and ASDs. Preliminary data show that mRNA levels of the short inducible homer1 isoform, homer1a, decrease after H2A.z1 depletion but increase when H2A.z2 is similarly depleted. Interestingly, gene ontology analysis of the microarray data reveals that several genes sensitive to H2A.z1, but not H2A.z2, depletion are known ASD and schizophrenia candidate genes, indicative of a possible hypervariant-specific role of H2A.Z in the etiology of these brain disorders. Thus, this proposal is designed to study these hypervariants in the context of neuronal function and synaptic plasticity. Three specific aims are proposed. First, the role of H2A.Z hypervariants will be studied in the rapid activity-induced induction of homer1a using RNA and chromatin immuno-precipitation techniques. Second, the DNA-binding sites of both H2A.Z isoforms across the entire genome and their roles in neuronal activity-dependent and -independent transcription will be studied by deep-sequencing of DNA and RNA from H2A.z1- or H2A.z2-depleted neurons. Third, the role of H2A.Z hypervariants in synaptic and non-synaptic neuronal function will be studied by electrophysiological and calcium imaging techniques.