Neuroepigenetic regulation of social status

描述（由申请人提供）：生物的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，已经涉及到这些变化。DNA甲基化，以前被认为只在发育过程中基因的印记中起作用，可以快速和可逆地作用于成年生物的基因表达模式。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导致体内显着的表型和行为变化，使用一个非常适合的鱼作为动物模型。在这个物种，A. burtoni，雄性存在两种不同的，可逆的表型：繁殖能力强的显性(D)雄性和繁殖能力弱的非显性（ND）雄性。表现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子，促性腺激素释放激素（GnRH1）包含在大脑视前区（POA）的神经元，改变它们的大小和连接，还有许多其他的改变，从身体颜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 > D的表型发生这些显著变化，反之，通过全局去甲基化诱导D > ND的表型发生这些显著变化。在拟建的实验中，我们将通过亚硫酸盐处理基因组DNA与超高通量测序（Illumina Genome analyzer）相结合，以单碱基对分辨率绘制甲基化基因组图谱。所有鱼类由于发育事件的甲基化状态将被共享。然而，我们将确定与每种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。我们将确定大脑中与社会地位变化有关的基因子集的位置。我们还将绘制甲基化变化相对于表型变化的时间过程，以发现这些变化是同时发生的还是顺序发生的。长期目标是了解甲基化如何与已知的脑回路相互作用以共同调节行为。我们使用的去甲基化试剂zebularine用于治疗癌症，我们的分析将是第一个提供其效果的行为分析。

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.