About this Research Topic
The mammalian oocyte maturation quality is critical for successful fertilization and following early embryo development, any errors will lead to birth defects. The oocytes undergo meiosis I and meiosis II, which include two round of chromosome segregation and one round of DNA replication. After germinal vesicle breakdown, the microtubules assemble the meiotic spindle and drive the chromosomes to the equatorial plate. Actin filaments and organelles such as mitochondria and Golgi apparatus are accumulated to the spindle periphery, and driven by the actin the meiotic spindle migrates to the oocyte cortex. Spindle assembly checkpoint monitors the microtubule-kinetochore attachment. Once the chromosome congression completes, anaphase-promoting complex/cyclosome (APC/C) actives and the homologous chromosomes are segregated. Actin filaments together myosin form contractile ring and initiates cytokinesis, which further induce the extrusion of a small polar body. The oocytes are arrested at the metaphase II until fertilization. For oocyte meiosis, the homologous chromosome segregation and asymmetric cell division are two unique feature compared with the somatic cells. And the molecular regulation of oocyte maturation still need large exploration.
Recently, the effects of environmental factors, diseases and food safety on the oocyte quality and maternal control are paid more attention. It is shown that the environmental exposure like air, soil, water and biota chemical pollutants, the diseases like obesity and diabetes, or contaminated foods intake like mycotoxins all could affect oocyte maturation quality, reduce the fertilization and early embryo development competence. These exposure could disrupt the meiosis resumption, cell cycle progression, the meiotic spindle organization, chromosome segregation, actin dynamics, organelle function and polar body extrusion. These exposed oocytes showed mitochondria dysfunction, DNA damage, oxidative stress, apoptosis/autophagy and reduced fertilization rate, indicating that the oocyte quality is affected. Although several solutions like melatonin and Resveratrol are proposed to protect the oocytes from toxic exposure through their effects on oxidative stress by the anti-oxidant functions, the effective solution and application are still need more studies.
This Research Topic aimed to focus on the molecular regulation and the toxic exposure on mammalian oocyte maturation. The expanding understanding about the molecular mechanism of oocyte quality control will provide exciting new insights into the oocyte maturation and early development.
We welcome the submission of Original Research Articles and Reviews that cover, but not limited to the following topics:
• Cell cycle control of oocytes
• Cytoskeleton dynamics of oocytes
• Organelle function of oocytes
• Environmental toxicity and disease on oocyte quality
• The potential solutions for reduced oocyte quality
Keywords: oocyte, cell cycle, spindle, cytokinesis, actin
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