Oct4基因在猪孤雌激活和体外受精早期胚胎中的表达特征

目的研究植入前胚胎发育重要基因Oct4在猪孤雌和体外受精胚胎中的表达特征。方法收集成熟卵母细胞、孤雌和体外受精2细胞、4细胞、8细胞胚胎和囊胚,做荧光即时定量PCR检测,以体外成熟的猪卵母细胞做对照分析相对表达量。结果孤雌组和体外受精组胚胎在8细胞期Oct4表达量均最高(P<0.05),在孤雌和体外受精组囊胚相对于其他时期Oct4表达量最低(P<0.05)。在同一时期孤雌和体外受精胚胎上Oct4表达并没有差异。结论多能性基因Oct4在卵裂发育时期表达量动态变化,孤雌胚胎在一定程度上可作为体外胚胎基因表达的模型,且不同的胚胎培养条件可能导致基因表达的差异。     

不同培养条件对鸡胚胎生殖细胞Oct4启动子DNA甲基化的影响

旨在在体外通过胚胎生殖细胞(EGC)和细胞外基质共同构建一个EGC的小生境(niche)模型,通过比较Oct4DNA甲基化的变化,研究niche中特有的表观遗传效应对胚胎生殖细胞自我更新的影响.构建EGC细胞标准培养方案(对照组)和改良培养方案(试验组),采用甲基化特异性PCR( MS-PCR)技术、RT-PCR技术,对比分析两种培养方案中Oct4启动子的甲基化状态,判断基因表达与其CpG岛甲基化的关系,分析DNA甲基化模式与EGC细胞自我更新的关系.结果显示,试验组可扩增出Oct4的非甲基化扩增产物,而对照组为其甲基化扩增产物,试验组Oct4表达水平明显高于对照组.试验组EGC生长状态明显好于对照组.试验表明,在改良培养条件下,Oct4基因启动子DNA甲基化程度较低,且与基因表达水平呈负相关,更有利于维持胚胎生殖细胞的自我更新状态.     

BMPs functionally replace Klf4 and support efficient reprogramming of mouse fibroblasts by Oct4 alone

Generation of induced pluripotent stem cells by defined factors has become a useful model to investigate the mechanism of reprogramming and cell fate determination. However, the precise mechanism of factor-based reprogramming remains unclear. Here, we show that Klf4 mainly acts at the initial phase of reprogramming to initiate mesenchymal-to-epithelial transition and can be functionally replaced by bone morphogenetic proteins (BMPs). BMPs boosted the efficiency of Oct4/Sox2-mediated reprogramming of mouse embryonic fibroblasts (MEFs) to ～1%. BMPs also promoted single-factor Oct4-based reprogramming of MEFs and tail tibial fibroblasts. Our studies clarify the contribution of Klf4 in reprogramming and establish Oct4 as a singular setter of pluripotency in differentiated cells.     

Over-expression of Oct4 in human esophageal squamous cell carcinoma

The Octamer 4 gene (Oct4) is a master pluripotency controller that has been detected in several types of tumors. Here, we examine the expression of Oct4 in human esophageal squamous cell carcinoma (ESCC). We found that punctate Oct4 protein was expressed in most (93.7%) ESCC samples but it was not observed in esophageal mucosa. Some ESCC cells had the capacity to form tumorospheres; those with an Oct4⁺-rich cell phenotype had increased proliferation and Oct4 mRNA levels compared to those of differentiated cells in culture or xenograft tumors. The over-expression of Oct4 in ESCCs suggests that it is a potential target for ESCC therapy. Oct4 could be a useful tumor marker in an immunohistochemical panel designed to differentiate between ESCC and esophageal mucosa. Expression of Oct4 in tumorospheres might indicate the presence of a population of ECSCs and its expression in xenograft tumors suggests that Oct4 is also associated with tumor metastasis.     

Evolutionary and Functional Analysis of the Key Pluripotency Factor Oct4 and Its Family Proteins

Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem (iPS) cells.Oct4 belongs to the POU domain family,which contains multiples genes with various ...