Fulka Helena, Aoki Fugaku
Institute of Animal Science, Prague, Czech Republic Institute of Molecular Genetics of the ASCR, Prague, Czech Republic
Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
Biol Reprod. 2016 Jun;94(6):143. doi: 10.1095/biolreprod.115.136093. Epub 2016 Mar 2.
In mammals, mature oocytes and early preimplantation embryos contain transcriptionally inactive structures termed nucleolus precursor bodies instead of the typical fibrillo-granular nucleoli. These nuclear organelles are essential and strictly of maternal origin. If they are removed from oocytes, the resulting embryos are unable to replace them and consequently fail to develop. Historically, nucleolus precursor bodies have been perceived as a passive repository site of nucleolar proteins that are required for embryos to form fully functional nucleoli. Recent results, however, contradict this long-standing dogma and show that these organelles are dispensable for nucleologenesis and ribosome biogenesis. In this article, we discuss the possible roles of nucleolus precursor bodies and propose how they might be involved in embryogenesis. Furthermore, we argue that these organelles are essential only shortly after fertilization and suggest that they might actively participate in centromeric chromatin establishment.
在哺乳动物中，成熟的卵母细胞和植入前早期胚胎含有被称为核仁前体的转录无活性结构，而不是典型的纤维颗粒状核仁。这些核细胞器至关重要且严格源自母体。如果将它们从卵母细胞中移除，产生的胚胎无法替换它们，因此无法发育。从历史上看，核仁前体一直被视为胚胎形成功能齐全的核仁所需的核仁蛋白的被动储存位点。然而，最近的研究结果与这一长期存在的教条相矛盾，表明这些细胞器对于核仁形成和核糖体生物合成并非必需。在本文中，我们讨论了核仁前体的可能作用，并提出它们可能如何参与胚胎发生。此外，我们认为这些细胞器仅在受精后不久是必不可少的，并表明它们可能积极参与着丝粒染色质的建立。
