Shin Hyejin, Kwon Sojung, Song Haengseok, Lim Hyunjung Jade
Department of Biomedical Science & Technology, Institute of Biomedical Science & Technology, Konkuk University, Seoul, Korea.
Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea.
PLoS One. 2014 Apr 10;9(4):e94708. doi: 10.1371/journal.pone.0094708. eCollection 2014.
The early growth response (Egr) family of zinc finger transcription factors consists of 4 members. During an investigation of Egr factor localization in mouse ovaries, we noted that Egr3 exhibits a subcellular localization that overlaps with the meiotic spindle in oocytes. Using Egr3-specific antibodies, we establish that Egr3 co-localizes with the spindle and cytosolic microtubule organizing centers (MTOCs) in oocytes during meiotic maturation. Notably, the Egr3 protein appears to accumulate around γ-tubulin in MTOCs. Nocodazole treatment, which induces microtubule depolymerization, resulted in the disruption of spindle formation and Egr3 localization, suggesting that Egr3 localization is dependent on the correct configuration of the spindle. Shortly after warming of vitrified oocytes, growing arrays of microtubules were observed near large clusters of Egr3. An in vitro microtubule interaction assay showed that Egr3 does not directly interact with polymerized microtubules. Egr3 localization on the spindle was sustained in early preimplantation mouse embryos, but this pattern did not persist until the blastocyst stage. Collectively, our result shows for the first time that the Egr3 a transcription factor may play a novel non-transcriptional function during microtubule organization in mouse oocytes.
锌指转录因子早期生长反应（Egr）家族由4个成员组成。在对小鼠卵巢中Egr因子定位的研究中，我们注意到Egr3表现出一种亚细胞定位，与卵母细胞中的减数分裂纺锤体重叠。使用Egr3特异性抗体，我们确定在减数分裂成熟过程中，Egr3与卵母细胞中的纺锤体和胞质微管组织中心（MTOC）共定位。值得注意的是，Egr3蛋白似乎在MTOC中的γ-微管蛋白周围积累。诺考达唑处理可诱导微管解聚，导致纺锤体形成和Egr3定位的破坏，这表明Egr3定位依赖于纺锤体的正确构型。玻璃化卵母细胞复温后不久，在大量Egr3簇附近观察到微管的生长阵列。体外微管相互作用试验表明，Egr3不与聚合微管直接相互作用。Egr3在纺锤体上的定位在植入前早期小鼠胚胎中持续存在，但这种模式在囊胚期之前并不持续。总的来说，我们的结果首次表明，转录因子Egr3可能在小鼠卵母细胞微管组织过程中发挥一种新的非转录功能。
