Investigating an Etiological Role of LINE-1 Retrotransposition in Birth Defects

研究 LINE-1 逆转录转座在出生缺陷中的病因学作用

基本信息

批准号：
8893427
负责人：
Wenfeng An
金额：
$ 21.89万
依托单位：
SOUTH DAKOTA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-06-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8893427
关键词：
Affect Age Aging Biology Cell Lineage Cells Congenital Abnormality DNA Transposable Elements Data Developed Countries Development Disease Environmental Impact Environmental Risk Factor Epigenetic Process Etiology Evaluation Event Failure Foundations Frequencies Future Gene Expression Genetic Polymorphism Genetic study Germ Cells Germ-Line Mutation Goals Hereditary Disease Human Human Genetics Inbred Strains Mice Incidence Infant Mortality Insertional Mutagenesis LacZ Genes Lead Link Long Interspersed Elements Measures Mediating Meiosis Modeling Mouse Strains Mus Mutagenesis Mutagens Mutation Neurofibromatosis 1 Outcome Paternal Age Patients Pattern Point Mutation Population Preventive Process Reporter Research Resolution Retrotransposition Retrotransposon Role Sampling Short Interspersed Nucleotide Elements Specificity Spermatocytes Spermatogenesis Spermatogonia Staging Stem cells Surveys Testicular Tissue Testing Time Tissues Transcriptional Regulation Transgenes Transgenic Mice Transgenic Organisms Work age effect age related child bearing clinically relevant cohort epigenetic regulation gain of function gene environment interaction gene function genetic analysis genome-wide infant death innovation insight male mammalian genome mouse development mouse model neurogenesis normal aging novel prevent public health relevance reproductive spatiotemporal

项目摘要

DESCRIPTION (provided by applicant): Non-LTR retrotransposons, including long interspersed elements type 1 (LINE-1s) and short interspersed elements, are highly abundant transposable elements in mammalian genomes. LINE-1s are autonomous: they not only replicate themselves but also mobilize Alus and SVAs. This process, termed retrotransposition, is inherently mutagenic and is responsible for >0.1% of spontaneous germline mutations in humans, including ~90 known cases of birth defects. Birth defects are the leading cause of infant death, but for the majority of birth defects the exact etiology is unknown, precluding effective preventive measures. Recent studies highlight the importance of environmental factors and epigenetic mechanisms, but how they lead to altered gene expression and function remains to be determined. Here, we propose to investigate an etiological role of LINE- 1 mediated insertional mutagenesis in major birth defects. We reason that such a role has been underappreciated because LINE-1 insertion polymorphisms are frequently missed by traditional genetic analyses. Indeed, a recent analysis of a cohort of unrelated neurofibromatosis type 1 patients, whose genetic alterations could not be explained by point mutations, revealed de novo insertions being the causative event for all 18 patients. The objective of this R21 application is o test the hypothesis that LINE-1 activities are developmentally regulated in the male germline, and that the frequency of retrotransposition increases in male germ cells with age. Mechanistically, a paternal age effect (PAE) may represent, at least in part, preferential retrotransposition in spermatogonia, or an age-related failure in the critical control mechanisms that regulate retrotransposons in spermatocytes, or both. In this proposal, we will use novel transgenic mouse models to specifically track LINE-1 mutagenesis burden during germ cell development, to determine whether de novo mutation by LINE-1 retrotransposition has a PAE, and to systematically profile LINE-1 expression pattern during mouse development. Our approach will generate novel data that are unattainable from human samples. It is expected to provide fundamental insights into mammalian genome biology and mutational mechanisms. It also represents a critical first step toward objective evaluation of the role of retrotransposon mutagens in sporadic human genetic disorders, with the potential to contribute to our understanding of mechanisms underlying PAEs on major birth defects.

描述（由申请人提供）：非LTR反转录转座子，包括长散布元件1型（LINE-1s）和短散布元件，是哺乳动物基因组中高度丰富的转座元件：它们不仅可以自我复制，而且可以自我复制。这一过程被称为逆转录转座，具有固有的诱变性，导致人类自发种系突变超过 0.1%，其中包括约 90 种已知突变。出生缺陷是婴儿死亡的主要原因，但大多数出生缺陷的确切病因尚不清楚，因此无法采取有效的预防措施，但最近的研究强调了环境因素和表观遗传机制的重要性，但它们是如何导致的。在此，我们建议研究 LINE-1 介导的插入突变在主要出生缺陷中的病因学作用，因为 LINE-1 插入多态性尚未得到充分重视。事实上，最近对一组不相关的 1 型神经纤维瘤患者进行的分析（其基因改变无法用点突变来解释）显示，从头插入是所有 18 名患者的致病事件。 R21 的应用是为了检验以下假设：LINE-1 活性在雄性生殖细胞中受到发育调节，并且雄性生殖细胞中逆转录转座的频率随着年龄的增长而增加。可能至少部分代表精原细胞中的优先逆转录转座，或调节精母细胞逆转录转座子的关键控制机制中与年龄相关的失败，或两者兼而有之。在本提案中，我们将使用新型转基因小鼠模型来特异性追踪 LINE-1。生殖细胞发育过程中的诱变负担，确定 LINE-1 逆转录转座引起的从头突变是否具有 PAE，并系统地分析小鼠发育过程中的 LINE-1 表达模式，我们的方法将产生无法获得的新数据。预计它将为哺乳动物基因组生物学和突变机制提供基本见解，这也代表着客观评估逆转录转座子诱变剂在散发性人类遗传性疾病中的作用的关键第一步，有可能有助于我们理解这一点。 PAEs 对主要出生缺陷的潜在机制。