Wellcome Trust, Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom.
Genes Dev. 2011 May 1;25(9):946-58. doi: 10.1101/gad.615211.
Amphibian oocytes can rapidly and efficiently reprogram the transcription of transplanted somatic nuclei. To explore the factors and mechanisms involved, we focused on nuclear actin, an especially abundant component of the oocyte's nucleus (the germinal vesicle). The existence and significance of nuclear actin has long been debated. Here, we found that nuclear actin polymerization plays an essential part in the transcriptional reactivation of the pluripotency gene Oct4 (also known as Pou5f1). We also found that an actin signaling protein, Toca-1, enhances Oct4 reactivation by regulating nuclear actin polymerization. Toca-1 overexpression has an effect on the chromatin state of transplanted nuclei, including the enhanced binding of nuclear actin to gene regulatory regions. This is the first report showing that naturally stored actin in an oocyte nucleus helps transcriptional reprogramming in a polymerization-dependent manner.
两栖类卵母细胞可以快速有效地重编程移植体的体细胞核转录。为了探究其中涉及的因素和机制，我们将重点放在细胞核肌动蛋白上，它是卵母细胞核（生发泡）中特别丰富的成分。细胞核肌动蛋白的存在和意义长期以来一直存在争议。在这里，我们发现核肌动蛋白聚合在多能性基因 Oct4（也称为 Pou5f1）的转录重新激活中起着至关重要的作用。我们还发现，一种肌动蛋白信号蛋白 Toca-1 通过调节核肌动蛋白聚合来增强 Oct4 的重新激活。Toca-1 的过表达对移植核的染色质状态有影响，包括增强核肌动蛋白与基因调控区域的结合。这是第一个表明卵母细胞核中天然储存的肌动蛋白以聚合依赖的方式帮助转录重编程的报告。
