National Institute of Biological Sciences, Beijing 102206, People's Republic of China.
Proc Natl Acad Sci U S A. 2010 Oct 12;107(41):17639-44. doi: 10.1073/pnas.1013185107. Epub 2010 Sep 27.
The mammalian oocyte possesses powerful reprogramming factors, which can reprogram terminally differentiated germ cells (sperm) or somatic cells within a few cell cycles. Although it has been suggested that use of oocyte-derived transcripts may enhance the generation of induced pluripotent stem cells, the reprogramming factors in oocytes are undetermined, and even the identified proteins composition of oocytes is very limited. In the present study, 7,000 mouse oocytes at different developmental stages, including the germinal vesicle stage, the metaphase II (MII) stage, and the fertilized oocytes (zygotes), were collected. We successfully identified 2,781 proteins present in germinal vesicle oocytes, 2,973 proteins in MII oocytes, and 2,082 proteins in zygotes through semiquantitative MS analysis. Furthermore, the results of the bioinformatics analysis indicated that different protein compositions are correlated with oocyte characteristics at different developmental stages. For example, specific transcription factors and chromatin remodeling factors are more abundant in MII oocytes, which may be crucial for the epigenetic reprogramming of sperm or somatic nuclei. These results provided important knowledge to better understand the molecular mechanisms in early development and may improve the generation of induced pluripotent stem cells.
哺乳动物卵母细胞具有强大的重编程因子，可以在几个细胞周期内重编程终末分化的生殖细胞（精子）或体细胞。尽管有人提出利用卵母细胞来源的转录本可能会增强诱导多能干细胞的生成，但卵母细胞中的重编程因子尚未确定，甚至卵母细胞中已鉴定的蛋白质组成也非常有限。在本研究中，收集了处于不同发育阶段的 7000 个小鼠卵母细胞，包括生发泡期、中期 II（MII）期和受精卵（胚胎）。我们通过半定量 MS 分析成功鉴定了生发泡卵母细胞中的 2781 种蛋白质、MII 期卵母细胞中的 2973 种蛋白质和胚胎中的 2082 种蛋白质。此外，生物信息学分析的结果表明，不同的蛋白质组成与不同发育阶段的卵母细胞特征相关。例如，特定的转录因子和染色质重塑因子在 MII 期卵母细胞中更为丰富，这对于精子或体细胞核的表观遗传重编程可能至关重要。这些结果为更好地理解早期发育中的分子机制提供了重要知识，并可能改善诱导多能干细胞的生成。
