The sperm LINC complex: The LINK between chromatin integrity, sperm motility and male fertility

精子 LINC 复合体：染色质完整性、精子活力和男性生育能力之间的联系

• 批准号: 431795952
• 负责人: Professor Dr. Klaus Steger
• 金额: --
• 依托单位: Sektion Molekulare Andrologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/431795952?language=en
• 关键词: sperm; LINC; complex; LINK; between

During spermiogenesis, histone-to-protamine exchange is followed by chromatin hypercondensation representing a sperm quality control checkpoint, as incomplete histone replacement and/or aberrant protamine-1 (PRM1) to protamine-2 (PRM2) ratios are associated with male subfertility. Within the last years, sperm chromatin developed into an emerging field of reproductive medicine. We were able to demonstrate that PRM2-deficient male mice are infertile due to highly elevated levels of fragmented sperm DNA and completely immotile sperm (Schneider et al. 2016). This observation together with the facts that (1) a second mouse line lacking PRM1 has been generated and (2) sperm from subfertile men are known to exhibit an aberrant PRM1 to PRM2 ratio, represent the basis for the proposed DFG-GACR project, where both applicants join their expertise and pool their lab resources in order to study the signal transduction from chromatin to cytoskeleton (motility) in more detail. Applicants hypothesize that decreased (subfertile men, heterozygous mice) or missing (homozygous mice) protamine expression is followed by incomplete chromatin condensation finally resulting in a dysfunctional LINC (Linker of Nucleoskeleton and Cytoskeleton) network system due to aberrant histone post-translational modifications (PTMs) that prevent binding of chromatin to the INM and/or aberrant expression of LINC complex components impeding exchange of information between nucleoskeleton and cytoskeleton. Due to group-specific expertise and pre-work, the Steger group will focus on interactions between sperm chromatin and nuclear membrane, whereas the Hortova group will concentrate on interactions between nuclear membrane and sperm cytoskeleton. Firstly, differences in both localization and interaction of selected nuclear (protamines, modified histones) and cytoplasmic (actin filaments, microtubules) proteins with LINC complex proteins (LBR, SUN, KASH) between wild-type and protamine-deficient mice will be identified. Secondly, data obtained in mice will be compared with (sub)fertile men. This complex approach will increase our knowledge on the crosstalk between molecular factors involved in the pathophysiology of human subfertility associated with incorrect histone to protamine exchange. Applicants share common scientific interest, but exhibit different technical expertise perfectly complementing each other. The proposed project will be embedded in a highly stimulating scientific environment, as Steger maintain two DFG-funded projects with Prof. Schorle (Bonn, D), who generated the protamine-deficient mouse lines applying CRISPR/Cas9 technology, and Hortova holds a GACR-funded project studying protein-protein interaction in gametes. Expected results on protein-protein interactions involved in the nucleus-cytoplasm communication will contribute to new aspects of our understanding of molecular regulation mechanisms of chromatin integrity and sperm motility.

在精子发生过程中，组蛋白与鱼精蛋白交换之后是染色质高凝聚，这是精子质量控制的一个检查点，因为组蛋白替代不完全和/或蛋白蛋白-1 （PRM1）与蛋白蛋白-2 （PRM2）比例异常与男性生育能力低下有关。在过去的几年里，精子染色质发展成为生殖医学的一个新兴领域。我们能够证明prm2缺陷的雄性小鼠由于精子DNA碎片化水平升高和精子完全不动而不育（Schneider等人，2016）。这一观察结果以及以下事实(1)已经产生了第二个缺乏PRM1的小鼠品系，(2)已知来自低生育能力男性的精子表现出异常的PRM1与PRM2比例，代表了拟议的DFG-GACR项目的基础，在该项目中，两位申请人加入他们的专业知识并汇集他们的实验室资源，以便更详细地研究从染色质到细胞骨架（运动）的信号转导。申请者假设生育能力下降的男性，杂合小鼠)或缺失（纯合小鼠）鱼精蛋白表达后，染色质浓缩不完全，最终导致功能失调的LINC（核骨架和细胞骨架连接物）网络系统，这是由于异常的组蛋白翻译后修饰（PTMs）阻止染色质与INM结合和/或LINC复合物组分的异常表达阻碍了核骨架和细胞骨架之间的信息交换。由于小组特定的专业知识和前期工作，Steger小组将专注于精子染色质和核膜之间的相互作用，而Hortova小组将专注于核膜和精子细胞骨架之间的相互作用。首先，鉴定野生型和精蛋白缺乏小鼠的核（精蛋白、修饰组蛋白）和细胞质（肌动蛋白丝、微管）蛋白与LINC复合物蛋白（LBR、SUN、KASH）在定位和相互作用方面的差异。其次，在小鼠中获得的数据将与（亚）生育能力的男性进行比较。这种复杂的方法将增加我们对与不正确的组蛋白与鱼精蛋白交换有关的人类低生育能力病理生理相关的分子因素之间的串扰的了解。申请人具有共同的科学兴趣，但表现出不同的技术专长，彼此互补。拟议的项目将嵌入一个高度刺激的科学环境中，因为Steger与Schorle教授（Bonn， D）共同维护两个dfg资助的项目，他们利用CRISPR/Cas9技术产生了蛋白蛋白缺乏的小鼠系，Hortova拥有一个gacr资助的项目，研究配子中的蛋白质-蛋白质相互作用。关于核-细胞质通讯中蛋白质-蛋白质相互作用的预期结果将有助于我们对染色质完整性和精子运动的分子调控机制的理解。