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Most imprinted genes are concerned with embryonic development, especially placental development. Here, we identified a placenta-specific imprinted gene Qpct. Our results show that Qpct is widely expressed during early embryonic development and can be detected in the telecephalon, midbrain, and rhombencephalon at E9.5b-E11.5. Moreover, Qpct is strikingly expressed in the brain, lung and liver in E15.5. Expression signals for Qpct achieved a peak at E15.5 during placental development and were only detected in the labyrinth layer in E15.5 placenta. ChIP assay results suggest that the modification of histone H3K4me3 can result in maternal activating of Qpct.

The function of long noncoding RNAs (lncRNAs) in cell differentiation and development have begun to be revealed in recent years. However, the expression pattern and mechanisms regulating lncRNAs are largely unknown during mammalian preimplantation development. LncRNAs expressed from Dlk1-Dio3 imprinted region have been linked to pluripotency of induced pluripotent cells (iPSCs). In this study we show that these lncRNAs (Gtl2, Rian and Mirg) are first expressed at the morula stage and gradually restricted to the inner cell mass (ICM) as the embryo differentiates into the blastocyst. Analysis of DNA methylation at IG-DMR and Gtl2-DMR showed no change during preimplantation while the presence of the activating histone modification H3K4me3 increased significantly from 8-cell to blastocyst stage, which may explain the expression activation. Additionally, knockdown of transcription factors (Oct4, Sox2 and Nanog) in blastocyst reduced the expression of Gtl2, indicating pluripotency factors regulate transcription of these lncRNAs. This study provides the spatiotemporal expression and dynamic changes of lncRNAs from Dlk1-Dio3 imprinted region in mouse preimplantation stage embryos and offers insight into the potential mechanisms responsible for Gtl2 activation., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Mouse Pde4d is located on chromosome 13 and serves many functions in important physiological processes involving cyclic adenosine monophosphate. In this study, imprinting analysis indicated that Pde4d exhibits a dynamic and specific allelic expression pattern during embryo development. This showed paternal-origin sex bias in embryonic day 9.5 (E9.5) whole embryos and placenta, and biallelic expression in the major embryonic organs and placenta at E15.5. In situ hybridization determined the spatiotemporal expression pattern of Pde4d in mouse embryos from the mid- to late-embryonic stages. This demonstrated that Pde4d was widely expressed in the neural tissues, including the forebrain, midbrain, hindbrain, and neural tube, at the mid-embryonic stage. By the late-embryonic stage, Pde4d was extensively detected throughout the developing organism, including in the liver, brain, lung, kidney, and tongue. In addition, methylation analyses indicated that tissue-specific CpG methylation of the Pde4d promoter was correlated with Pde4d mRNA expression in major E15.5 tissues. Furthermore, stage-specific CpG methylation of the Pde4d promoter was associated with gene expression in the liver at three developmental stages. Our results suggest that Pde4d might serve specific biological functions in regulating the development process of the mouse embryo, and that CpG methylation of the Pde4d promoter may play an important role in regulating Pde4d at a transcriptional level., (Copyright © 2013 Elsevier Inc. All rights reserved.)