The role of sperm inner acrosomal membrane proteins in acrosomal biogenesis and fertilization

精子顶体内膜蛋白在顶体生物发生和受精中的作用

• 批准号: 192093-2012
• 负责人: Oko, Richard
• 金额: $ 2.91万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=546035
• 关键词: role; sperm; inner; acrosomal; membrane

Fertilization is the cornerstone of development where the two differentiated cells, sperm and egg set the stage for embryogenesis and beyond, for which competency of the gametes is essential. Yet only rudimentary knowledge is available on the molecules and mechanisms involved in sperm-egg interactions leading to zygotic development. This is underscored in consideration that 30-50 % of male-factor infertility cases have no known cause. Our strategy in gaining an understanding of these mechanisms is to isolate and molecularly dissect sperm compartments (e.g., acrosome and perinuclear theca) that are involved in the fertilization process. The identities of the proteins provides clues to the compartment's significance and allows us to design specific probes (e.g., antibodies, and wild type and mutant recombinants and competitive inhibitors) to test the predicted functions and mechanisms of these proteins during fertilization and/or spermiogenesis. Utilizing this approach, under the mandate of the NSERC Discovery Grant, my student trainees and I have investigated the function of the inner acrosomal membrane (IAM). This sperm component plays a critical role during fertilization as it is exposed by the acrosome-reaction and then binds the sperm firmly to the zona pellucida (ZP) of the egg, a compulsory step for subsequent IAM-directed sperm penetration of this extracellular matrix. Before our study the proteins of the IAM were unexplored. We have identified and characterized the following IAM proteins: IAM38, binding receptor to ZP; MMP2, potential ZP penetrating enzyme; proacrosin, potential MMP activating enzyme; SPACA1, trans-membrane protein which potentially organizes and attaches these proteins to the IAM; SubH2Bv, KAPa and KAPß which form a complex and potentially direct the acrosomic vesicle to the nucleus during spermiogenesis. The present proposal intends to validate the potential functions of these proteins and elucidate their mechanisms of action. The knowledge gained would unquestionably lead to a better understanding of the origins of sperm infertility defects and their diagnosis. It could also serve to improve application of Assisted Reproductive Technologies and to design a contraceptive.

受精是发育的基石，其中两个分化的细胞，精子和卵子为胚胎发生及以后奠定了基础，配子的能力是必不可少的。然而，只有基本的知识是可利用的分子和机制，涉及精卵相互作用，导致合子的发展。考虑到30- 50%的男性因素不育病例没有已知的原因，这一点得到了强调。我们理解这些机制的策略是分离和分子解剖精子隔室（例如，顶体和核周膜）参与受精过程。蛋白质的身份为区室的意义提供了线索，并允许我们设计特异性探针（例如，抗体，以及野生型和突变重组体和竞争性抑制剂），以测试这些蛋白质在受精和/或精子发生过程中的预测功能和机制。利用这种方法，在NSERC发现基金的授权下，我和我的学生学员研究了顶体内膜（IAM）的功能。这种精子成分在受精过程中起着关键作用，因为它通过顶体反应暴露出来，然后将精子牢固地结合到卵子的透明质膜（ZP）上，这是随后IAM指导的精子穿透这种细胞外基质的必要步骤。在我们的研究之前，IAM的蛋白质尚未被探索。我们已经鉴定并表征了以下IAM蛋白：IAM 38，ZP结合受体; MMP 2，潜在的ZP穿透酶;顶体蛋白原，潜在的MMP活化酶; SPACA 1，潜在地组织并将这些蛋白质附着到IAM的跨膜蛋白; SubH 2Bv、KAPa和KAPl 3，它们形成复合物并在精子发生期间潜在地将顶体囊泡引导到细胞核。目前的建议旨在验证这些蛋白质的潜在功能，并阐明其作用机制。所获得的知识无疑将有助于更好地了解精子不育缺陷的起源及其诊断。它还可以用于改善辅助生殖技术的应用和设计避孕药具。