Mechanisms of Oocyte Maturation and the Role of 1-MA with GVBD

Students: Joshua Oldt, Joshua Malak

Faculty Mentor: Lisa Hua

Biology

College of Science, Technology, and Business

Oocyte maturation is a critical process consisting of separating the germinal vesicle from the oocyte to prepare for fertilization, involving intricate signaling mechanisms and cellular interactions. A key event in this maturation is Germinal Vesicle Breakdown (GVBD), where the nuclear envelope dissolves, allowing meiotic progression from prophase I to metaphase I. In many marine invertebrates and echinoderms, Gonadotropin Stimulating Substance (GSS), an analog to vertebrate Gonadotropic Hormone (GH), triggers the release of 1-methyladenosine (1-MA) from ovarian follicle cells, replacing progesterone and initiating GVBD. The signaling cascade begins when 1-MA binds to surface receptors, leading to the activation of Maturation Promoting Factor (MPF) via a c-mos-dependent MAP kinase phosphorylation cascade. This cascade promotes nuclear envelope breakdown and cytoskeletal reorganization, preparing the oocyte for fertilization. Additionally, the presence of Ca²⁺ in filtered seawater (FSW) facilitates oocyte aggregation and enhances GSS release. These molecular interactions coordinate oocyte maturation, highlighting evolutionarily conserved mechanisms with species-specific adaptations.