Mitalipov Shoukhrat M, Kuo Hung-Chih, Hennebold Jon D, Wolf Don P
Oregon National Primate Research Center, Beaverton, Oregon 97006, USA.
Biol Reprod. 2003 Dec;69(6):1785-92. doi: 10.1095/biolreprod.103.019455. Epub 2003 Jul 30.
The POU (Pit-Oct-Unc)-domain transcription factor, Oct-4, has become a useful marker of pluripotency in the mouse. It is found exclusively in mouse preimplantation-stage embryos after embryonic genome activation and is a characteristic of mouse embryonic stem (ES) cells, and its absence in knockout mice precludes inner cell mass (ICM) formation in blastocysts. Expression of Oct-4 has also been associated with pluripotency in primate cells. Here, we undertook a systematic study of Oct-4 expression in rhesus macaque preimplantation embryos produced by intracytoplasmic sperm injection and in ES cells before and after exposure to differentiating conditions in vitro. We also evaluated Oct-4 expression as a means of monitoring the extent of reprogramming following somatic cell nuclear transfer. Oct-4 was detected by reverse transcription-polymerase chain reaction and immunocytochemistry with a monoclonal antibody. Monkey pronuclear-stage zygotes and cleaving embryos up to the 8-cell stage showed no detectable Oct-4. Nuclear staining for Oct-4 first became obvious at the 16-cell stage, and a strong signal was observed in morula and compact morula stages. Both ICM and trophectodermal cell nuclei of monkey early blastocysts were positive for Oct-4. However, the signal was diminished in trophectodermal cells of expanded blastocysts, whereas expression remained high in ICM nuclei. Similar to the mouse, hatched monkey blastocysts showed strong Oct-4 expression in the ICM, with no detectable signal in the trophectoderm. Undifferentiated monkey ES cells derived from the ICM of in vitro-produced blastocysts expressed Oct-4, consistent with their pluripotent nature, whereas ES cell differentiation was associated with signal loss. Therefore, Oct-4 expression in the monkey, as in the mouse, provides a useful marker for pluripotency after activation of the embryonic genome. Finally, the observed lack or abnormal expression of Oct-4 in monkey nuclear transfer embryos suggests inadequate nuclear reprogramming.
POU（Pit-Oct-Unc）结构域转录因子Oct-4已成为小鼠多能性的一个有用标记。它仅在胚胎基因组激活后的小鼠植入前阶段胚胎中发现，是小鼠胚胎干细胞（ES细胞）的一个特征，在基因敲除小鼠中其缺失会阻止囊胚中内细胞团（ICM）的形成。Oct-4的表达也与灵长类细胞的多能性有关。在此，我们对通过胞浆内精子注射产生的恒河猴植入前胚胎以及体外暴露于分化条件前后的ES细胞中Oct-4的表达进行了系统研究。我们还评估了Oct-4表达作为监测体细胞核移植后重编程程度的一种手段。通过逆转录聚合酶链反应和使用单克隆抗体的免疫细胞化学检测Oct-4。猴原核期受精卵和直至8细胞期的分裂胚胎未检测到Oct-4。Oct-4的核染色在16细胞期首次变得明显，在桑椹胚和致密桑椹胚阶段观察到强信号。猴早期囊胚的ICM和滋养外胚层细胞核Oct-4均为阳性。然而，在扩张囊胚的滋养外胚层细胞中信号减弱，而在ICM细胞核中表达仍然很高。与小鼠相似，孵化后的猴囊胚在ICM中显示出强Oct-4表达，在滋养外胚层中未检测到信号。源自体外产生囊胚ICM的未分化猴ES细胞表达Oct-4，与其多能性质一致，而ES细胞分化与信号丧失有关。因此，与小鼠一样，猴中的Oct-4表达为胚胎基因组激活后的多能性提供了一个有用标记。最后，在猴核移植胚胎中观察到的Oct-4缺乏或异常表达表明核重编程不足。
