L1 retrotransposition during spermatogenic failure

生精失败期间 L1 逆转座

• 批准号: 9809811
• 负责人: Wenfeng An
• 金额: $ 7.3万
• 依托单位: SOUTH DAKOTA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-04 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9809811
• 关键词: Counseling; Couples; DNA; DNA Methylation; DNA Modification Methylases; DNA Sequence; Development; Enzymes; Evaluation; Failure; Family; Foundations; Frequencies; Gene Silencing; Genes; Genetic; Genetic Transcription; Genome; Genomic DNA; Genomic Instability; Genomics; Germ Cells; Growth; Histones; Infertility; Knock-out; Knockout Mice; Knowledge; Lead; Long Interspersed Elements; Male Infertility; Measures; Mediating; Methylation; Modeling; Modification; Mus; Mutagens; Mutate; Mutation; Parasites; Pathway interactions; Proteins; Public Health; RNA; Regulation; Reporter; Retrotransposition; Retrotransposon; Role; Spermatids; Spermatocytes; Spermatogenesis; Spermatogonia; Spermiogenesis; Supporting Cell; Surveys; Testing; Time; TimeLine; Transgenes; Transgenic Mice; Up-Regulation; aged; derepression; fetal; insight; male; male fertility; mouse model; mutant; novel; piRNA; spermatogonial arrest

PROJECT SUMMARY/ABSTRACT Infertility is a significant public health problem. According to the 2006-2010 National Survey of Family Growth, approximately 10% of US couples aged 15-44 failed to conceive after one year of trying. Unfortunately, the genetic underpinnings for the majority of the infertile cases remain unknown, hindering proper counselling and treatment efforts. As a mutational mechanism, the role for retrotransposons in infertility has been increasingly recognized. Retrotransposons, including long interspersed element type 1 (LINE1 or L1), are abundant genomic DNA sequences that amplify themselves in the genome through an RNA intermediate. To maintain the integrity of the germline genome, germ cells have evolved an elaborate regulatory network to transcriptionally and post-transcriptionally silence these unrestful genomic parasites. Perhaps more than a coincidence, all genes that have been implicated in retrotransposon control in mouse germ cells are also essential for male fertility. The general observation is, when each of these genes is mutated, mouse spermatogenesis is blocked at discrete stages and accompanied by L1 upregulation at both RNA and protein levels. A critical gap in our knowledge is whether L1 derepression is a cause or consequence of the spermatogenic arrest. How might uncontrolled and untimely activation of retrotransposons disrupt spermatogenesis? The most straightforward hypothesis is that massive L1 retrotransposition instigates genomic instability and ultimately leads to germ cell demise. So far, due to technical difficulties, few studies have attempted to test this hypothesis. Using a novel transgenic mouse model for L1 retrotransposition, we recently demonstrated, for the first time, that the derepression of retrotransposon expression does lead to increased retrotransposition in mutant spermatocytes of Mov10l1 knockout mice. In this proposal, we will take advantage of this new reporter mouse line and, in conjunction with additional infertility mouse models, seek to determine whether other stages of germ cells support L1 retrotransposition. The proposed project will provide much needed insights into L1 retrotransposition potential in discrete stages of male germ cell development and lay the foundation for a critical evaluation of the role of retrotransposition in male infertility.

项目概要/摘要 不孕不育是一个重大的公共卫生问题。根据2006-2010年全国家庭调查 增长，大约 10% 的 15-44 岁美国夫妇在尝试一年后未能怀孕。很遗憾， 大多数不孕症病例的遗传基础仍然未知，阻碍了适当的咨询 和治疗努力。作为一种突变机制，逆转录转座子在不孕症中的作用已被证实 越来越被认可。逆转录转座子，包括长散布元件类型 1（LINE1 或 L1） 丰富的基因组 DNA 序列，通过 RNA 中间体在基因组中自我扩增。到 为了维持生殖系基因组的完整性，生殖细胞进化出了复杂的调控网络 转录和转录后沉默这些不安的基因组寄生虫。或许不止一个 巧合的是，所有与小鼠生殖细胞中逆转录转座子控制有关的基因也都是 对男性生育能力至关重要。一般观察是，当这些基因中的每一个发生突变时，小鼠 精子发生在不同的阶段被阻断，并伴随着 L1 RNA 和蛋白质的上调 水平。我们知识中的一个关键差距是 L1 去抑制是 L1 的原因还是结果 生精停滞。逆转录转座子的不受控制和不合时宜的激活会如何破坏 精子发生？最直接的假设是大规模的 L1 逆转录转座会引发 基因组不稳定并最终导致生殖细胞死亡。迄今为止，由于技术困难，研究较少 试图检验这个假设。使用新型转基因小鼠模型进行 L1 逆转录转座，我们 最近首次证明逆转录转座子表达的去抑制确实会导致 Mov10l1 敲除小鼠的突变精母细胞中逆转录转座增加。在本提案中，我们将采取 利用这种新的报告小鼠系的优势，并结合其他不孕小鼠模型，寻求 确定生殖细胞的其他阶段是否支持 L1 逆转录转座。拟议的项目将提供 对雄性生殖细胞发育的不同阶段中 L1 逆转录转座潜力的深入了解和 为严格评估逆转录转座在男性不育中的作用奠定基础。