Exploring Sperm Competency

研究问题 * 我们对男性生殖和评估精子功能的理解存在差距。雄性对生殖的贡献并不止于卵母细胞的受精。精子传递父亲的基因组，这是随后正常胚胎发育和健康多产后代生长所必需的。然而，精子很容易受到环境压力的影响。与卵母细胞和大多数体细胞不同，精子不具备纠正损伤的细胞机制。因此，环境损伤会降低精子创造健康胚胎的能力，这些胚胎将发育成正常的后代。我的研究将解决精子表观基因组对环境的敏感性。表观基因组定义了基因组的哪些基因在细胞中表达。通过表观遗传修饰，包括DNA甲基化、翻译后组蛋白修饰介导的染色质包装和非编码RNA，可以在不改变基因组序列的情况下调节基因表达。表观遗传模式是在早期发育过程中产生的，对分化至关重要。与基因组不同，表观基因组对环境信号做出反应，在环境、改变的基因表达和表型之间提供联系。最新的文献表明，精子表观基因组可能在胚胎发育和后代健康中发挥作用。* 一般假设 * 环境压力诱导精子染色质的表位突变，从而阻碍正常胚胎和后代的产生。* 方法 * 我们将使用冷冻保存作为可能影响精子的环境应激的模型，使用牛和猪系统作为农业重要物种的模型，以及实验室小鼠，以验证这一假设。将对新鲜和冷冻保存的精子进行表观基因组分析：将使用还原亚硫酸氢盐测序（RRBS）评估甲基化组，将使用染色质免疫沉淀结合下一代测序监测特异性翻译后组蛋白修饰，并将通过下一代RNA测序评估精子转录组。将使用新鲜和冷冻保存的精子进行体外受精，并监测胚胎的发育能力。我们将比较使用新鲜和冻融精子产生的胚胎的转录组。* 影响 * 这项研究将证明精子表观基因组在胚胎发育过程中的重要性，这可能会影响后代的生产力和健康。这些知识对动物生产和濒危物种的保护很有意义。它将提供有关冷冻保存对表观基因组影响的基本知识，表观基因组可以转移到精子以外的细胞类型。该计划将支持2名博士生，并介绍多达5名本科生进行研究。

Research Problem***There are gaps in our understanding of male reproduction and assessing sperm function. The male's contribution to reproduction does not end at fertilization of the oocyte. The sperm delivers the paternal genome, which is required for subsequent normal embryo development and the growth of healthy and productive offspring.***Sperm, however, are vulnerable to environmental stressors. Unlike the oocyte and most somatic cells, sperm do not possess the cellular machinery to correct damage. Therefore, environmental insults can reduce the ability of the sperm to create a healthy embryo that will develop into normal offspring. My research will address the susceptibility of the sperm epigenome to the environment.***The epigenome defines which genes of the genome are expressed in cells. Regulation of gene expression without altering genome sequence is possible by epigenetic modifications, including DNA methylation, chromatin packaging mediated by post-translational histone modifications and non-coding RNAs. Epigenetic patterns are generated during early development and are crucial for differentiation. Unlike the genome, the epigenome responds to environmental signals, providing a connection between the environment, altered gene expression and phenotype. The most current literature suggests that the sperm epigenome may play a role in embryo development and, presumably, offspring health. ***General Hypothesis***Environmental stressors induce epimutations in the sperm chromatin, thereby impeding the production of normal embryos and offspring. ***Approach***We will use cryopreservation as a model of environmental stress that can affect sperm using the bovine and porcine systems as models of agriculturally-significant species, as well as the lab mouse, to test this hypothesis. Epigenome analyses will be carried out on fresh and cryopreserved sperm: the methyome will be assessed using Reduced Representation Bisulfite Sequencing (RRBS), specific posttranslational histone modifications will be monitored using chromatin immunoprecipitation coupled with next-generation sequencing, and the sperm transcriptome will be assessed by next generation RNA sequencing. In vitro fertilization will be carried out with fresh and cryopreserved sperm, and the developmental competence of the embryos will be monitored. We will compare the transcriptomes of embryos produced using fresh and frozen-thawed sperm. ***Impact***This research will demonstrate the importance of the sperm epigenome during embryo development that can impact offspring productivity and health. Such knowledge is of interest to animal production and for conservation of endangered species. It will provide basic knowledge about the impact of cryopreservation on the epigenome, which can be transferred to cell types other than sperm. This program will support 2 PhD students and introduce as many as 5 undergraduates to research.