Department of Animal Science, Faculty of Veterinary Sciences, Universidad de Concepcion, Avenida Vicente Mendez 595, Chillán, Chile,
In Vitro Cell Dev Biol Anim. 2013 Oct;49(9):657-67. doi: 10.1007/s11626-013-9650-0. Epub 2013 Jul 12.
Nuclear transfer (NT) is associated with epigenetic reprogramming of donor cells. Expression of certain genes in these cells might facilitate their expression in the NT embryo. This research was aimed to investigate the effect of constitutive expression of OCT4 in bovine somatic cells used for NT on the developmental potential of derived cloned embryos as well as in the expression of pluripotency markers in the Day-7 resulting embryos. Cloned blastocysts were generated from five cell lines that expressed OCT4. Pools of blastocysts were screened to detect OCT4, SOX2, and NANOG by qPCR. In vitro-fertilized time-matched blastocysts were used as controls. The development potential was assessed on the basis of blastocysts rate; grading and total cell counts at Day 7. OCT4 expression in the cell lines positively correlates with blastocysts rate (r = 0.92; p = 0.02), number of grade I blastocysts (r = 0.96; p = 0.01), and total cell number (r = 0.98; p = 0.002). The high expression of OCT4 in the cell line did not improve the final outcome of cloning. Somatic expression of OCT4 lead to increased expression of OCT4 and SOX2 in cloned grade I blastocysts; however, there was a bigger variability in OCT4 and SOX2 (p = 0.03; p = 0.02) expression in the embryos generated from cells expressing highest levels of OCT4. Probably the higher variability in OCT4 expression in cloned embryos is due to incorrect reprogramming and incapability of the oocyte to correct for higher OCT4 levels. For that reason, we concluded that OCT4 expression in somatic cells is not a good prognosis marker for selecting cell lines.
核转移（NT）与供体细胞的表观遗传重编程有关。这些细胞中某些基因的表达可能有助于它们在 NT 胚胎中的表达。本研究旨在探讨用于 NT 的牛体细胞核移植中 OCT4 的组成型表达对衍生克隆胚胎的发育潜能以及 Day-7 胚胎中多能性标记物表达的影响。从表达 OCT4 的五个细胞系中生成克隆胚泡。通过 qPCR 筛选胚泡池以检测 OCT4、SOX2 和 NANOG。将体外受精的时间匹配的胚泡用作对照。根据胚泡率、第 7 天的分级和总细胞计数评估发育潜力。细胞系中 OCT4 的表达与胚泡率呈正相关（r = 0.92；p = 0.02）、I 级胚泡的数量（r = 0.96；p = 0.01）和总细胞数（r = 0.98；p = 0.002）。细胞系中 OCT4 的高表达并没有改善克隆的最终结果。OCT4 在体细胞核移植中的表达导致克隆 I 级胚泡中 OCT4 和 SOX2 的表达增加；然而，在表达最高水平 OCT4 的细胞产生的胚胎中，OCT4 和 SOX2 的表达存在更大的变异性（p = 0.03；p = 0.02）。在克隆胚胎中，OCT4 表达的变异性可能是由于不正确的重编程和卵母细胞无法纠正更高水平的 OCT4 所致。因此，我们得出结论，OCT4 在体细胞中的表达不是选择细胞系的良好预后标志物。
