Three experiments were conducted to examine the in vitro development of preimplantation embryos from the prolific Chinese Meishan pig. Experiment 1 was conducted to assess whether Meishan embryos would develop in vitro and retain their viability, whereas Exp. 2 and 3 examined the developmental pattern of Meishan embryos. In all three experiments, Yorkshire embryos served as a contemporary compa...

In mouse ovarian follicles, granulosa cells but not oocytes take up glucose to provide the oocyte with nourishments for energy metabolism. Diabetes-induced hyperglycemia or glucose absorption inefficiency consistently causes granulosa cell apoptosis and further exerts a series of negative impacts on oocytes including reduced meiosis resumption rate, low oocyte quality and preimplantation embryo...

Human preimplantation embryo development involves complex cellular and molecular events that lead to the establishment of three cell lineages in the blastocyst: trophectoderm, primitive endoderm, and epiblast. Owing to limited resources of biological specimens, our understanding of how the earliest lineage commitments are regulated remains narrow. Here, we examined gene expression in 241 indivi...

The totipotent zygote gives rise to cells with differing identities during mouse preimplantation development. Many studies have focused on analyzing the spatio-temporal dependencies during these lineage decision processes and much has been learnt by tracing transgenic marker gene expression up to the blastocyst stage and by analyzing the effects of genetic manipulations (knockout/ overexpressio...

Genome-wide epigenetic reprogramming by demethylation occurs in early mouse embryos and primordial germ cells. In early embryos many single-copy sequences become demethylated both by active and passive demethylation, whereas imprinted gene methylation remains unaffected. In primordial germ cells single-copy and imprinted sequences are demethylated, presumably by active demethylation. Here we in...

The elucidation, unravelling and understanding of the molecular basis of transcriptional control during preimplantation development is of utmost importance if we are to intervene and eliminate or reduce abnormalities associated with growth, disease and infertility by applying assisted reproduction. Importantly, these studies should enhance our knowledge of basic reproductive biology and its app...

The transition from meiosis to mitosis, classically defined by fertilization, is a fundamental process in development. However, its mechanism remains largely unexplored. In this paper, we report a surprising gradual transition from meiosis to mitosis over the first eight divisions of the mouse embryo. The first cleavages still largely share the mechanism of spindle formation with meiosis, durin...

Cellular differentiation and multicellular development require the programmed expression of coregulated suites of genetic loci dispersed throughout the genome. How do functionally diverse loci come to share common regulatory motifs? A new paper finds that retrotransposons (RTEs) may play a role in providing common regulation to a group of functions expressed during the development of oocytes an...

The XIV Workshop on the Development and Function of Reproductive Organs was held in Rome, from 14-17 September, 2008, at the Congress Centre of the University of Tor Vergata of Villa Mondragone (Rome, Italy). The Workshop was conceived to be a survey of the events from the formation of the gamete precursors, the primordial germ cells, to the development of the preimplantation embryo through fem...

Gametogenesis (spermatogenesis and oogenesis) is accompanied by the acquisition of gender-specific epigenetic marks, such as DNA methylation, histone modifications and regulation by small RNAs, to form highly differentiated, but transcriptionally silent cell-types in preparation for fertilisation. Upon fertilisation, extensive global epigenetic reprogramming takes place to remove the previously...