Identification and differential expression patterns of porcine OCT4 variants

• DOI: 10.1530/rep-14-0403
• Publication Date: 2014-10-24T04:07:03Z
• Authors: Jae Yeon Hwang; Jong-Nam Oh; Dong-Kyung Lee; Kwang-Hwan Choi; Chi-Hun Park; Chang-Kyu Lee
• Keywords: 0301 basic medicine; Base Sequence; Reverse Transcriptase Polymerase Chain Reaction; Swine; Blotting, Western; Molecular Sequence Data; Cell Differentiation; Embryo, Mammalian; Real-Time Polymerase Chain Reaction; Alternative Splicing; Mice; 03 medical and health sciences; Blastocyst; Gene Expression Regulation; Sequence Homology, Nucleic Acid; Animals; Humans; Octamer Transcription Factors; Protein Isoforms; Female; RNA, Messenger; Embryonic Stem Cells

OCT4encoded byPOU5F1has a crucial role of maintaining pluripotency in embryonic stem cells during early embryonic development and severalOCT4variants have been identified in mouse and human studies. The objective of this study was to identify different variants ofOCT4and analyze their expression patterns in preimplantation porcine embryos and various tissues. In this study, we showed thatPOU5F1transcribes its three variants, namelyOCT4A,OCT4B, andOCT4B1. TheOCT4Btranscript consists of exons identical to the major form of theOCT4variant,OCT4A, with a differential N-terminal domain-coding exon. The structure ofOCT4B1mRNA was the same as that ofOCT4BmRNA, but harbored a cryptic exon. Based on these findings, the transcription levels were investigated and found thatOCT4BandOCT4B1made up ∼20% among the variants in the embryonic stage and this indicates thatOCT4AmRNA is dominantly expressed during preimplantation embryo development. In addition,OCT4BmRNA was detected in all tissues examined, whileOCT4AandOCT4B1were detected only in testis but not in other tissues examined.OCT4B1showed inversely correlated expression withSOX2andNANOGexpression. 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 porcineOCT4gene can potentially encode three variants (OCT4A,OCT4B, andOCT4B1), and they are differentially expressed and would have roles dissimilar between each other in preimplantation embryos and various adult tissues.