The potential of the oocyte and its relationship with the ovarian follicular niche

• Grant number: 23/08037-2
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): September 01, 2023
• Effective date (End): August 31, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Lawrence Charles Smith
• Grantee: Marilin Ivask
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Associated research grant: 21/09886-8 - Epigenetic maturation of the oocyte and totipotence: the potential of the oocyte and its relationship with the ovarian follicular niche, AP.SPEC

Abstract

For the oocyte to be able to give rise to an embryo and, consequently, a full-term individual, it must undergo two classic types of maturation: nuclear and cytoplasmic. While cytoplasmic maturation is characterized by the accumulation of mRNAs and proteins, nuclear maturation is mainly characterized by the condensation and segregation of chromosomes. However, recently with the advent of powerful techniques to investigate the epigenome it has been possible to characterize the oocyte epigenome. With regard to DNA methylation, oocytes acquire this as they increase in size during folliculogenesis, the follicular niche being indirectly responsible for providing a suitable microenvironment for epigenetic modifications in the oocyte chromatin, a process called "oocyte epigenetic maturation" . Among all genes regulated by DNA methylation, imprinted genes are crucial for proper embryonic development and are particularly sensitive to manipulations during reproductive biotechnologies. Furthermore, recent studies indicate that oocyte metabolic activity may be affected by methylations at the mitochondrial DNA level in oocytes and granulosa cells. Therefore, a better understanding of the epigenetic mechanisms that coordinate oocyte maturation and its relationship with the acquisition of totipotency is essential. (AU)