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Implanting Blastocyst (implanting + blastocyst)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Differential expression of transcriptional repressor snail gene at implantation site in mouse uterus

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2006
Xing-Hong Ma
Abstract The snail superfamily of zinc-finger transcription factors is involved in pronounced cell movements during both embryonic development and tumor progression. This study was to examine snail expression in mouse uterus during early pregnancy and its regulation under pseudopregnancy, delayed implantation, steroid hormone treatment, and artificial decidualization by in situ hybridization and immunohistochemistry. There was a low level of snail mRNA signal and immunostaining in mouse uteri on day 1,4 of pregnancy. When embryo implanted on day 5, both snail mRNA signal and immunostaining were strongly detected in the subluminal stroma immediately surrounding the implanting blastocyst, but not detected in the inter-implantation sites. Under delayed implantation, there was no detectable snail expression. After delayed implantation was terminated by estrogen treatment and embryo implanted, there was a strong level of snail mRNA and immunostaining in the subluminal stroma surrounding the implanting blastocyst, which was similar to that on day 5 of pregnancy. Furthermore, there was no detectable snail expression in mouse uterus on day 5 of pseudopregnancy. From day 6,8 of pregnancy, both snail mRNA signal and immunostaining were detected in the decidua. Our data suggest that snail may play an important role during mouse embryo implantation. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source]

Differential expression and activation of Stat3 during mouse embryo implantation and decidualization

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2004
Chun-Bo Teng
Abstract Signal transducer and activator of transcription (STATs) can be activated by many cytokines and growth factors. Stat3, a member of STAT family, is essential for embryonic development. Stat3 is specifically activated during mouse embryo implantation. This study was to investigate the expression, activation, and regulation of Stat3 in mouse uterus during early pregnancy, pseudopregnancy, delayed implantation, artificial decidualization, and hormonal treatments using in situ hybridization and immunohistochemistry. There was a strong level of Stat3 phosphorylation in the luminal epithelium only at the midnight of day 4 pregnancy, which coincides with attachment reaction between the blastocyst and luminal epithelium. However, there was no detectable Stat3 phosphorylation at the corresponding period during pseudopregnancy. On day 5 of pregnancy, Stat3 phosphorylation was strongly observed in the luminal epithelium and the stroma surrounding the implanting blastocyst at implantation sites, but not at the inter-implantation sites. Stat3 phosphorylation was also not detected on day 5 of pseudopregnancy. Stat3 phosphorylation was at a high level in the decidual cells on days 6,8 of pregnancy. Under artificial decidualization, Stat3 was also phosphorylated in the decidual cells. In the ovariectomized mice, there was no Stat3 expression and activation in the uterus. Progesterone had no obvious effects. However, Stat3 mRNA expression and phosphorylation were significantly stimulated by estrogen treatment. Our data suggest that Stat3 phosphorylation may be important for mouse embryo implantation and decidualization, and may also be regulated by maternal estrogen. Mol. Reprod. Dev. 69: 1,10, 2004. © Wiley-Liss, Inc. [source]

Peroxisome proliferator-activated receptor delta expression and regulation in mouse uterus during embryo implantation and decidualization

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2003
Nai-Zheng Ding
Abstract The aim of this study was to examine the expression and regulation of peroxisome proliferator-activated receptor (PPAR) PPAR, gene in mouse uterus during early pregnancy by in situ hybridization and immunohistochemistry. PPAR, expression under pseudopregnancy, delayed implantation, hormonal treatment, and artificial decidualization was also investigated. There was a very low level of PPAR, expression on days 1,4 of pregnancy. On day 5 when embryo implanted, PPAR, expression was exclusively observed in the subluminal stroma surrounding the implanting blastocyst. No corresponding signals were seen in the uterus on day 5 of pregnancy. There was no detectable PPAR, signal under delayed implantation. Once delayed implantation was terminated by estrogen treatment and embryo implanted, a strong level of PPAR, expression was induced in the subluminal stroma surrounding the implanting blastocyst. Estrogen treatment induced a moderate level of PPAR, expression in the glandular epithelium, while progesterone treatment had no effects in the ovariectomized mice. A strong level of PPAR, expression was seen in the decidua on days 6,8 of pregnancy. PPAR, expression was also induced under artificial decidualization. These data suggest that PPAR, expression at implantation sites require the presence of an active blastocyst and may play an essential role for blastocyst implantation. Mol. Reprod. Dev. 66: 218,224, 2003. © 2003 Wiley-Liss, Inc. [source]

Changes in histone modification upon activation of dormant mouse blastocysts

ANIMAL SCIENCE JOURNAL, Issue 6 2007
Tamako MATSUHASHI
ABSTRACT Gene expression in the implanting blastocyst is altered by stimulation with estrogen secreted from maternal ovaries. In the present study, to understand the mechanism regulating the changes in gene expression, diverse histone modifications in blastocysts were studied using a delayed implantation model, in which embryos were kept in a dormant state in the uterus by maternal ovariectomy and progesterone treatment, and then activated by injection with estrogen. Total transcriptional activity increased markedly in activated embryos, and immunocytochemistry with antibodies recognizing specific histone modifications revealed differential modification of several histones in the trophectoderm (TE) and inner cell mass (ICM) of dormant and activated embryos. High levels of histone H3 lysine 9 (H3K9) dimethylation, which suppresses gene expression, were observed in the ICM, but not in the TE, of dormant embryos, and the levels decreased when the embryos were activated, consistent with changes in transcriptional activity. Substitution of histone H3.3, a variant of H3, for dominant H3.1 increased in activated embryos, suggesting that histone substitution is involved in inducing gene expression associated with activation. In the nucleus, H3.3 was mainly localized in the nucleoli of activated embryos but not in those of dormant ones. In contrast, there were no obvious differences in the trimethylation of histone H3K9 or the acetylation of histones H3K9, H3K18 and H4K12 between dormant and activated embryos. These results suggest that a decrease in H3K9 dimethylation contributes to the acquisition of implantation competence by releasing genes from suppression. In addition, histone H3.3 substitution seems to be involved in global gene activation and facilitates the prompt recovery of dormant blastocysts to the active state by inducing rRNA synthesis, resulting in an increase in translational activity. [source]