Chiaratti Marcos R, Garcia Bruna M, Carvalho Karen F, Macabelli Carolina H, Ribeiro Fernanda Karina da Silva, Zangirolamo Amanda F, Sarapião Fabiana D, Seneda Marcelo M, Meirelles Flávio V, Guimarães Francisco E G, Machado Thiago S
Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil.
Anim Reprod. 2018 Aug 17;15(3):231-238. doi: 10.21451/1984-3143-AR2018-0069.
Oocyte mitochondria are increased in number, smaller, and rounder in appearance than mitochondria in somatic cells. Moreover, mitochondrial numbers and activity are narrowly tied with oocyte quality because of the key role of mitochondria to oocyte maturation. During oocyte maturation, mitochondria display great mobility and cluster at specific sites to meet the high energy demand. Conversely, oocyte mitochondria are not required during early oogenesis as coupling with granulosa cells is sufficient to support gamete's needs. In part, this might be explained by the importance of protecting mitochondria from oxidative damage that result in mutations in mitochondrial DNA (mtDNA). Considering mitochondria are transmitted exclusively by the mother, oocytes with mtDNA mutations may lead to diseases in offspring. Thus, to counterbalance mutation expansion, the oocyte has developed specific mechanisms to filter out deleterious mtDNA molecules. Herein, we discuss the role of mitochondria on oocyte developmental potential and recent evidence supporting a purifying filter against deleterious mtDNA mutations in oocytes.
卵母细胞中的线粒体数量增加，体积更小，外观比体细胞中的线粒体更圆。此外，由于线粒体对卵母细胞成熟的关键作用，线粒体数量和活性与卵母细胞质量密切相关。在卵母细胞成熟过程中，线粒体表现出极大的移动性，并聚集在特定部位以满足高能量需求。相反，在早期卵子发生过程中不需要卵母细胞线粒体，因为与颗粒细胞的耦合足以满足配子的需求。部分原因可能是保护线粒体免受导致线粒体DNA（mtDNA）突变的氧化损伤的重要性。考虑到线粒体仅由母亲遗传，具有mtDNA突变的卵母细胞可能导致后代患病。因此，为了平衡突变扩展，卵母细胞已经发展出特定机制来过滤有害的mtDNA分子。在此，我们讨论线粒体对卵母细胞发育潜力的作用以及支持对卵母细胞中有害mtDNA突变进行纯化筛选的最新证据。
