Krüppel-like protein Gli-similar 1 (GLIS1) is known as a direct reprogramming factor for the generation of induced pluripotent stem cells. The objective of this study was to investigate the role of GLIS1 in the preimplantation development of bovine embryos. GLIS1 transcripts in in vitro-matured oocytes and 1-cell to 4-cell stage embryos were detected, but they were either absent or at trace lev...

Oocyte maturation is associated with suppression of transcriptional activity. Consequently, gene expression during oocyte maturation, fertilization and early embryo development, until zygotic genome activation (ZGA) is primarily regulated by translational activation of maternally derived mRNAs. Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse...

Successful embryonic development is dependent on the temporal and stage-specific expression of appropriate genes. Currently, information on specific gene expression during early cleavage-stage embryos before zygotic gene activation (ZGA) is limited. In the present study, we compare gene expression between porcine 2-cell and blastocyst stage parthenotes to identify genes that are specifically or...

In mammals, totipotent embryos are formed by fusion of highly differentiated gametes. Acquisition of totipotency concurs with chromatin remodeling of parental genomes, changes in the maternal transcriptome and proteome, and zygotic genome activation (ZGA). The inefficiency of reprogramming somatic nuclei in reproductive cloning suggests that intergenerational inheritance of germline chromatin c...

Transcriptional control requires epigenetic changes directed by mitochondrial tricarboxylic acid (TCA) cycle metabolites. In the mouse embryo, global epigenetic changes occur during zygotic genome activation (ZGA) at the 2-cell stage. Pyruvate is essential for development beyond this stage, which is at odds with the low activity of mitochondria in this period. We now show that a number of enzym...

Stored maternal factors in oocytes regulate oocyte differentiation into embryos during early embryonic development. Before zygotic gene activation (ZGA), these early embryos are mainly dependent on maternal factors for survival, such as macromolecules and subcellular organelles in oocytes. The genes encoding these essential maternal products are referred to as maternal effect genes (MEGs). MEGs...

In the mouse, new embryonic transcription appears after fertilization during the S phase of the first cell cycle in the male pronucleus, while the female pronucleus is largely repressed (Bouniol et al., 1995; Christians et al., 1995; Majumder et al., 1993; Ram and Schultz, 1993). Both pronuclei then become equally repressed during the subsequent G2 phase, concomitant with de novo synthesis of h...

The activity of HMG-CoA reductase (HMGR) is tightly regulated, in part through post-transcriptional mechanisms that are mediated by nonsterol products of mevalonate metabolism. Previous reports have suggested that these mediators are derived from farnesyl pyrophosphate (FPP). Recent studies have implicated FPP hydrolysis products (e.g., farnesol), the squalene synthetase (SQS) reaction products...

In general, cloning undifferentiated preimplantation embryos (blastomeres) or embryonic stem cells is more efficient than cloning differentiated somatic cells. Therefore, there has been an assumption that tissue-specific stem cells might serve as efficient donors for nuclear transfer because of the undifferentiated state of their genome. Here, we show that this is not the case with adult hemato...

The fertilized oocyte begins cleavage, leading to zygotic gene activation (ZGA), which re-activates the resting genome to acquire totipotency. In this process, genomic function is regulated by the dynamic structural conversion in the nucleus. Indeed, a considerable number of genes that are essential for embryonic development are located near the pericentromeric regions, wherein the heterochroma...