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

人们对表观遗传过程在心理健康维持或放松管制中的作用知之甚少。 鉴于以下事实，理解这些表观遗传过程是至关重要的 大脑的许多发育和精神障碍，如自闭症谱系障碍(ASDS)， 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 已报道的H_2A.Z超变异体(H_2A.z1和H_2A.z2)彼此之间只有三个差异 氨基酸。尽管有如此细微的差异，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个人中 受H2A.z1或H2A.z2基因敲除影响的基因，不到5%受到缺乏这两种异构体的影响， 强烈提示这些异构体在神经基因调控中的功能在很大程度上不重叠。一 这种受H2A.z亚型强烈调控的基因是同源基因，当突变时，已知是一种风险 精神分裂症和自闭症的因素。初步数据显示，短可诱导的Hmer 1的mRNA水平 同工异构体Homer1a在H_2A.z1耗尽后减少，但在H_2A.z2类似耗尽时增加。 有趣的是，对微阵列数据的基因本体论分析显示，几个对H2A.z1敏感的基因， 但不是H2A.z2，耗竭是已知的ASD和精神分裂症候选基因，表明可能存在 H_2A.Z在这些脑部疾病的病因学中的超变特异性作用。因此，这项提议旨在 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 建议。首先，将研究H_2A.Z超变异体在快速活性诱导的 Homer1a使用RNA和染色质免疫沉淀技术。第二，两者的DNA结合部位 全基因组中的H_2A.Z亚型及其在神经元活动依赖和非依赖中的作用 转录将通过对H_2A.z1或H_2A.z2缺失的DNA和RNA进行深度测序来研究 神经元。第三，研究H_2A.Z超变异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.