The apportionment of zygotic totipotency: Origins, mechanisms and consequences for natural and assisted reproduction in the mouse model

合子全能性的分配：小鼠模型自然和辅助生殖的起源、机制和后果

• 批准号: 450038723
• 负责人: Privatdozent Dr. Michele Boiani
• 金额: --
• 依托单位: Institut für Biostatistik und Informatik in Medizin und Alternsforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/450038723?language=en
• 关键词: apportionment; zygotic; totipotency; Origins; mechanisms

In mammals, the two blastomeres resulting from the 1st zygotic division are deemed equally totipotent, able to form two monozygotic twins. However, the first cleavage plane differs among embryos, distributing the constituents of the ooplasm differently among the two blastomeres, questioning equal potentiality. We propose that intracytoplasmic sperm injection –widely used in assisted reproduction– helps to investigate potentiality in a controlled manner, by imposing the site of oocyte fertilization and thus cleavage orientation. Motivated by Xenopus and sea urchin data, we hypothesize that the mouse blastomeres are most similar to each other when the 1st cleavage plane runs along the animal-vegetal axis, yet they are most different from each other when it runs perpendicular. The transcriptomes of blastomeres will be combined with those of our recent meta-analysis of conventional 2-cell embryos, where transcription patterns of, e.g., Tead1 and Cops3 do correlate with blastomere similarity as per our hypothesis. Additional gene(s) X may be revealed in the present study. To reach beyond correlation and establish causality, we deplete gene products directly at the protein level in oocytes prior to fertilization. We assess developmental consequences and subject Tead1-, Cops3- and gene X-depleted embryos to proteomics to confirm the specificity of the protein depletion. During the course of the project we shall answer two questions: 1) if and how the orientation of the 1st cleavage plane introduces functional variation among the blastomeres; and 2) if and how maternal protein deposits in mammalian oocytes are decisive for potentiality and development.

在哺乳动物中，由第一次合子分裂产生的两个卵裂球被认为是同样全能的，能够形成两个单卵双胞胎。然而，第一卵裂平面在胚胎之间不同，卵质的成分在两个卵裂球之间的分布不同，质疑相等的潜力。我们建议，胞浆内单精子注射-广泛用于辅助生殖-有助于调查的潜力，在一个可控的方式，通过施加卵母细胞受精的网站，从而卵裂方向。受非洲爪蟾和海胆数据的启发，我们假设小鼠卵裂球在第一卵裂面沿着动物-植物轴时彼此最相似，而在第一卵裂面垂直时彼此最不相同。卵裂球的转录组将与我们最近对传统2细胞胚胎的荟萃分析相结合，其中转录模式，例如，Tead 1和Cops 3确实与我们的假设中的卵裂球相似性相关。在本研究中可能发现其他基因X。为了超越相关性并建立因果关系，我们在受精前直接在卵母细胞的蛋白质水平上耗尽基因产物。我们评估发育后果，并将Tead 1，Cops 3和基因X耗尽的胚胎进行蛋白质组学研究，以确认蛋白质耗尽的特异性。在项目过程中，我们将回答两个问题：1）第一卵裂面的方向是否以及如何在卵裂球中引入功能变异; 2）哺乳动物卵母细胞中的母体蛋白质沉积是否以及如何决定潜力和发育。