As revealed by the present study, connexin gene expression in the endometrium is regulated via two distinct mechanisms: The first is through an ERa-dependent signaling pathway during preimplantation; the second, an ERa-independent pathway, occurs during embryo implantation or artificial decidualization. As shown previously, maternal progesterone suppresses expression of Cx26 and Cx43 in rat endometrium during […]

ER-Mediated Regulation of Cx26 and Cx43 Gene Expression in Rat Endometrium Induction of the gap junction Cx26 in the epithelial cells and Cx43 in the developing decidual cells of rat endometrium is dependent on the blastocyst during implantation, but it is highly regulated by ovarian steroid hormones during preimplantation. To further analyze the signaling pathways […]

Animal Care Adult female Sprague-Dawley rats were housed under defined conditions with a temperature of 22 ± 1°C, an atmospheric humidity of 55% ± 10% (mean±SEM), and a 12L:12D photoperiod. They were fed standard pellet food and provided with water ad libitum. All animal experiments were approved by the institutional animal care committee of the […]

An indispensable precondition for successful implantation of the mammalian blastocyst into the endometrium is precise synchronization of the physiological and cell biological events of the developing blastocyst and the endometrium for successful interaction with one another. Disruption of this synchrony in the differentiation process leads to failure in implantation. The molecular signals involved are of […]

Since the original observations of BrdU incorporation in the male pronucleus of one-cell mouse embryos, the functional meaning of such an early transcriptional activity of a mammalian embryo has been unclear. In fact, RNA molecules synthesized at this stage and their encoded proteins, if any, still have to be identified, and their functional significance is […]

Mid-One-Cell Embryos Respond to Isolation from the In Vivo Environment by Nuclear Migration of HSF1 Studying the intracellular localization of heat shock factors HSF1 and HSF2 during mouse preimplantation development, we found that, when mid-one-cell embryos were fixed within the Fallopian tubes, HSF1 had a cytoplasmic localization and was fully absent from pronuclei (Fig. 1A), […]

Animals Growing and full-grown ovarian oocytes at the dictyate stage of mei-osis were obtained from ovaries of 12- to 14-day old and of eCG-treated, 40- to 60-day old Swiss-CD1 female mice, respectively. Preimplantation embryos were routinely obtained by crossing eCG-hCG-primed B6D2F1 females with B6D2F1 males. All mice were from Charles River Italia (Calco, Italy) or […]

Fertilization in mammals activates a developmental clock that leads the newly formed embryo to progressively shift from the maternal to the zygotic genome expression (zygotic genome activation, ZGA). In the mouse, this process is initiated very soon after fertilization and de novo synthesis of RNA is consistently observed for the first time during the S […]