Editorial: Quality Control of Mammalian Oocyte Meiotic Maturation: Causes, Molecular Mechanisms and Solutions.

The mammalian oocyte maturation quality is critical for successful fertilization and following early embryo development any errors will lead to birth defects, which might also cause infertility. The oocyte maturation includes two rounds of chromosome segregation and one round of DNA replication. Oocyte meiosis starts with germinal vesicle breakdown, and once a small polar body is extruded, the oocyte is arrested at metaphase II until fertilization. Previous studies have found that centrosome-mediated microtubule functions are important for the meiotic spindle organization in oocytes (Schatten and Sun, 2015) and that actin filaments drive spindle migration and cytokinesis during oocyte maturation (Duan and Sun, 2019), which is regulated by multiple factors such as Rab GTPases and Formins (Wang et al., 2019; Pan et al., 2020). Recently, the effects of environmental exposure, diseases, and food safety on oocyte quality and maternal control have received more attention. It has been shown that environmental exposure for example to air, soil, water, and biota chemical pollutants, diseases like obesity and diabetes, or the intake of contaminated foods like mycotoxins all could affect oocyte maturation quality, reduce fertilization and early embryo development competence (Ou et al., 2019; Gallo et al., 2020). This Research Topic, including seven reviews and 31 original research articles, offers critical and new insights into the causes and molecular mechanism of oocyte quality control, with particular insights into the cell cycle and cytoskeleton dynamics, mitochondria Ca2+ uptake, epigenetic modification, effects of environmental exposure, disease, and aging, and potential molecules for the protection of oocyte quality.