Neuroepigenetic regulation of social status

描述（由申请人提供）：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由神经回路的修改引起的。然而，最近，另一种互补机制DNA甲基化与这些变化有关。DNA甲基化以前被认为只在发育过程中的基因印记中起作用，但在成年生物中可以快速可逆地作用于基因表达模式。我们提出了新的实验，使用非常适合的慈鲷作为动物模型来测试DNA甲基化是否以及在哪里会导致体内显着的表型和行为变化。在该种中，A. burtoni，雄性存在于两种不同的可逆表型中的任一种：生殖能力显性（D）雄性和生殖能力不全非显性（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器，促性腺激素释放激素（GnRH1）包含在大脑的视前区（POA）的神经元，改变它们的大小和连接性，还有许多其他的修改，从身体颜色到受体丰度的分子调节。我们已经证明，我们可以通过整体甲基化诱导ND > D的表型发生这些显著变化，反之，通过整体去甲基化诱导D > ND的表型发生这些显著变化。在所提出的实验中，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（Illumina Genome Analyser）相结合，以单碱基对分辨率制作甲基化的基因组图谱。由于发育事件，所有鱼类的甲基化状态将被共享。然而，我们将确定与每个不同的表型在自然行为的遭遇或作为一个结果的甲基化调节剂治疗相关的甲基化事件。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大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作用的行为分析。

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.