A dispersed cytoplasmic distribution of mitochondria is a hallmark of normal cellular organization. Here, we have utilized the expression of exogenous Trak2 in mouse oocytes and embryos to disrupt the dispersed distribution of mitochondria by driving them into a large cytoplasmic aggregate. Our findings reveal that aggregated mitochondria have minimal impact on asymmetric meiotic cell divisions of the oocyte. In contrast, aggregated mitochondria during the first mitotic division result in daughter cells with unequal sizes and increased micronuclei. Further, in two-cell embryos, microtubule-mediated centering properties of the mitochondrial aggregate prevent nuclear centration, distort nuclear shape, and inhibit DNA synthesis and the onset of embryonic transcription. These findings demonstrate the motor protein-mediated distribution of mitochondria throughout the cytoplasm is highly regulated and is an essential feature of cytoplasmic organization to ensure optimal cell function.

中文翻译：

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植入前胚胎中聚集的线粒体分布破坏核形态、功能和发育潜力


线粒体分散的细胞质分布是正常细胞组织的标志。在这里，我们利用小鼠卵母细胞和胚胎中外源 Trak2 的表达，通过驱动线粒体形成大的细胞质聚集体来破坏线粒体的分散分布。我们的研究结果表明，聚集的线粒体对卵母细胞不对称减数分裂的影响最小。相反，第一次有丝分裂期间聚集的线粒体会导致子细胞大小不均且微核增加。此外，在双细胞胚胎中，微管介导的线粒体聚集体的居中特性可防止核居中、扭曲核形状并抑制 DNA 合成和胚胎转录的开始。这些发现表明，运动蛋白介导的线粒体在整个细胞质中的分布受到高度调控，并且是细胞质组织的基本特征，以确保最佳的细胞功能。