Deciphering the cellular and molecular mechanisms underlying mammalian sperm-egg fusion

破译哺乳动物精卵融合的细胞和分子机制

• 批准号: 22K15103
• 负责人: Lu Yonggang
• 金额: $ 2.91万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2022
• 资助国家: 日本
• 起止时间: 2022-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-22K15103/
• 关键词: Fertilization; Sperm-egg fusion; Spermiogenesis; piRNA biogenesis; Male infertility; Male reproduction; Genome editing; Cell biology; Sperm

In the fiscal year of 2022, I published three research articles and one review article as the first author.In Tang, Lu et al. 2022 PNAS, we resolved the crystal structure of human TMEM95 by X-ray crystallography and generated monoclonal antibodies against human TMEM95 and IZUMO1. To investigate the molecular function of TMEM95, we exploited the nature that human sperm can fertilize zona-free golden hamster eggs. Using Fab fragments of the antibodies, we found that IZUMO1 Fabs ablate sperm-egg binding, in corroboration with our recent finding in mice and rats (Matsumura et al. 2022 Front Cell Dev Biol). In contrast, TMEM95 Fabs do not affect sperm-egg binding, but reduce sperm-egg fusion, suggesting that TMEM95 plays a role distinct to IZUMO1. Further, we engineered TMEM95-Fc fusion protein and discovered that the recombinant protein binds the hamster egg plasma membrane, indicating that TMEM95 has an egg receptor.In Lu et al. 2023 PNAS, we discovered that 1700029I15Rik, a type II transmembrane protein localized to the ER, regulates the biosynthesis of acrosomal membrane glycoproteins required for sperm-egg interaction. This pathway is independent from Calmegin-mediated biosynthesis of sperm plasma membrane proteins, suggesting that acrosomal and plasma membrane proteins are processed in a spatiotemporal manner.Additionally, in Lu et al. (2023) Andrology, we reported that ADAD2, in association with other RNA-binding proteins (e.g., MIWI, RNF17), regulates piRNA biogenesis in testis. Moreover, ADAD2 forms novel granules with and stabilizes RNF17 in pachytene spermatocytes.

在2022财年，我以第一作者身份发表了3篇研究文章和1篇综述文章，在Tang，Lu et al. 2022 PNAS中，我们通过X射线晶体学解析了人TMEM 95的晶体结构，并生成了针对人TMEM 95和IZUMO 1的单克隆抗体。为了研究TMEM 95的分子功能，我们利用人类精子可以使无透明带的金黄地鼠卵受精的性质。使用抗体的Fab片段，我们发现IZUMO 1 Fab消除精卵结合，这与我们最近在小鼠和大鼠中的发现相印证（Matsumura等人，2022 Front Cell Dev Biol）。相比之下，TMEM 95 Fab不影响精卵结合，但减少精卵融合，表明TMEM 95发挥与IZUMO 1不同的作用。此外，我们改造了TMEM 95-Fc融合蛋白，发现重组蛋白结合仓鼠卵质膜，表明TMEM 95具有卵受体。在Lu et al. 2023 PNAS中，我们发现1700029 I15 Rik，一种定位于ER的II型跨膜蛋白，调节精卵相互作用所需的顶体膜糖蛋白的生物合成。该途径独立于Calmegin介导的精子质膜蛋白的生物合成，表明顶体和质膜蛋白以时空方式加工。MIWI，RNF 17）调节睾丸中的皮尔纳生物合成。此外，ADAD 2与RNF 17形成新的颗粒并稳定粗线期精母细胞中的RNF 17。

项目成果

ADAD2 functions in spermiogenesis and piRNA biogenesis in mice

• DOI: 10.1111/andr.13400
• 发表时间: 2023-02-14
• 期刊: ANDROLOGY
• 影响因子: 4.5
• 作者: Lu，Yonggang;Nagamori，Ippei;Ikawa，Masahito
• 通讯作者: Ikawa，Masahito

Eukaryotic fertilization and gamete fusion at a glance

• DOI: 10.1242/jcs.260296
• 发表时间: 2022-11-01
• 期刊: JOURNAL OF CELL SCIENCE
• 影响因子: 4
• 作者: Lu，Yonggang;Ikawa，Masahito
• 通讯作者: Ikawa，Masahito