Neuroepigenetic regulation of social status

描述(申请人提供)：生物体的DNA序列在动物的一生中基本保持不变，因此长期的表型和行为变化被认为是神经回路改变的结果。然而，最近，另一种互补机制，DNA甲基化，被牵连到这些变化中。DNA甲基化以前被认为只在发育过程中的基因印记过程中起作用，现在可以快速和可逆地作用于成年生物体的基因表达模式。我们提出了新的实验来测试DNA甲基化是否以及在哪里可以在体内导致戏剧性的表型和行为变化，使用非常合适的慈鱼作为动物模型。在该物种中，雄性以两种不同的可逆表型之一存在：繁殖能力强的显性(D)雄性和繁殖能力不强的非显性(ND)雄性。表型之间的转换是社会环境的结果，并在几分钟内产生生理变化，最终导致生殖轴的重塑。生殖能力的主要调节因素是促性腺激素释放激素(GnRH1)，含有大脑视前区(POA)的神经元，改变其大小和连接性，并有许多其他修饰，从身体着色到受体丰度的分子调节。我们已经证明，我们可以通过全局甲基化诱导ND和GT；D的这些显着的表型变化，反之亦然，通过全局去甲基化来诱导D&GT；ND的这些表型变化。在拟议的实验中，我们将通过将基因组DNA的亚硫酸氢盐处理与超高通量测序相结合(Illumina Genome Analyser)，以单碱基对的分辨率绘制甲基化的基因组图谱。所有鱼类由于发育事件而产生的甲基化状态将被共享。然而，我们将确定与每个不同表型相关的甲基化事件，以响应自然行为遭遇或作为甲基化调节剂治疗的结果。这些新的结果将为甲基化和行为表型之间的关系提供重要的见解。我们将确定与社会地位变化有关的基因子集在大脑中的位置。我们还将绘制甲基化变化与表型变化相关的时间进程图，以发现这些变化是同步的还是连续的。长期目标是了解甲基化如何与已知的大脑回路相互作用，共同调节行为。我们使用的去甲基化试剂ZeBularine用于治疗癌症，我们的分析将首次提供其影响的行为分析。

DESCRIPTION (provided by applicant): An organism's DNA sequence remains fundamentally unchanged over an animal's life so that long term phenotypic and behavioral changes are thought to result from modifications in neural circuits. Recently, however, another, complementary mechanism, DNA methylation, has been implicated in these changes. DNA methylation, previously thought to act only during the imprinting of genes during development, can act quickly and reversibly on gene expression patterns in adult organisms. We propose novel experiments to test whether and where DNA methylation can lead to dramatic phenotypic and behavioral changes in vivo using a well suited cichlid fish as an animal model. In this species, A. burtoni, males exist in either of two distinct, reversible phenotypes: reproductively competent dominant (D) males and reproductively incompetent non-dominant (ND) males. The switch between phenotypes is a consequence of the social environment and produce physiological changes within minutes, ultimately resulting in remodeling of the reproductive axis. The main regulator of reproductive competence, gonadotropin releasing hormone (GnRH1) containing neurons in the pre-optic area (POA) of the brain, change their size and connectivity and there are numerous other modifications from body coloration to molecular regulation in receptor abundance. We have shown that we can induce these dramatic changes in phenotype from ND > D by global methylation and conversely from D > ND by global demethylation. In the proposed experiments, we will make genomic maps of methylation at single-base-pair resolution by combining bisulfite treatment of genomic DNA with ultra-high-throughput sequencing (Illumina Genome Analyser). The methylation state of all fish due to developmental events will be shared. However, we will identify methylation events associated with each distinct phenotype in response to natural behavioral encounters or as a result of treatment with methylation-regulating agents. These novel results will provide important insights into the relationship between methylation and behavioral phenotype. We will identify where in the brain the subset of genes implicated in social status change are located. We will also map the time course of methylation changes relative to phenotype change to discover whether these are simultaneous or sequential. The long-term objectives are to understand how methylation interacts with known brain circuitry to co-regulate behavior. The demethylating reagent we use, zebularine, is used to treat cancer and our analysis will be the first to provide a behavioral analysis of its effects.