Hwang Jae Yeon, Oh Jong-Nam, Lee Dong-Kyung, Choi Kwang-Hwan, Park Chi-Hun, Lee Chang-Kyu
Department of Agricultural BiotechnologyAnimal Biotechnology Major, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, KoreaInstitute of Green Bio Science and TechnologySeoul National University, Kangwon-do 232-916, Korea.
Department of Agricultural BiotechnologyAnimal Biotechnology Major, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, KoreaInstitute of Green Bio Science and TechnologySeoul National University, Kangwon-do 232-916, Korea Department of Agricultural BiotechnologyAnimal Biotechnology Major, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, KoreaInstitute of Green Bio Science and TechnologySeoul National University, Kangwon-do 232-916, Korea
Reproduction. 2015 Jan;149(1):55-66. doi: 10.1530/REP-14-0403. Epub 2014 Oct 23.
OCT4 encoded by POU5F1 has a crucial role of maintaining pluripotency in embryonic stem cells during early embryonic development and several OCT4 variants have been identified in mouse and human studies. The objective of this study was to identify different variants of OCT4 and analyze their expression patterns in preimplantation porcine embryos and various tissues. In this study, we showed that POU5F1 transcribes its three variants, namely OCT4A, OCT4B, and OCT4B1. The OCT4B transcript consists of exons identical to the major form of the OCT4 variant, OCT4A, with a differential N-terminal domain-coding exon. The structure of OCT4B1 mRNA was the same as that of OCT4B mRNA, but harbored a cryptic exon. Based on these findings, the transcription levels were investigated and found that OCT4B and OCT4B1 made up ∼20% among the variants in the embryonic stage and this indicates that OCT4A mRNA is dominantly expressed during preimplantation embryo development. In addition, OCT4B mRNA was detected in all tissues examined, while OCT4A and OCT4B1 were detected only in testis but not in other tissues examined. OCT4B1 showed inversely correlated expression with SOX2 and NANOG expression. OCT4A protein was specifically localized to the nuclei, whereas OCT4B was mainly localized to the cytoplasm of the porcine embryos at the blastocyst stage. The findings of this study reveal that the porcine OCT4 gene can potentially encode three variants (OCT4A, OCT4B, and OCT4B1), and they are differentially expressed and would have roles dissimilar between each other in preimplantation embryos and various adult tissues.
由POU5F1编码的OCT4在早期胚胎发育过程中对维持胚胎干细胞的多能性起着关键作用，并且在小鼠和人类研究中已鉴定出几种OCT4变体。本研究的目的是鉴定OCT4的不同变体，并分析它们在植入前猪胚胎和各种组织中的表达模式。在本研究中，我们表明POU5F1转录其三种变体，即OCT4A、OCT4B和OCT4B1。OCT4B转录本由与OCT4变体的主要形式OCT4A相同的外显子组成，具有不同的N端结构域编码外显子。OCT4B1 mRNA的结构与OCT4B mRNA相同，但含有一个隐蔽外显子。基于这些发现，研究了转录水平，发现OCT4B和OCT4B1在胚胎阶段的变体中占约20%，这表明OCT4A mRNA在植入前胚胎发育过程中占主导表达。此外，在所有检测的组织中均检测到OCT4B mRNA，而OCT4A和OCT4B1仅在睾丸中检测到，在其他检测组织中未检测到。OCT4B1的表达与SOX2和NANOG的表达呈负相关。OCT4A蛋白特异性定位于细胞核，而OCT4B主要定位于囊胚期猪胚胎的细胞质中。本研究结果表明，猪OCT4基因可能编码三种变体（OCT4A、OCT4B和OCT4B1），它们在植入前胚胎和各种成年组织中差异表达，且功能各异。
