Project description:BACKGROUND: Litter size in pigs is a major factor affecting the profitability in the pig industry. The peri-implantation window in pigs is characterized by the coordinated interactions between the maternal uterine endometrium and the rapidly elongating conceptuses and represents a period of time during which a large percentage of the developing conceptuses are lost. However, the gene expression and regulatory networks in the endometrium contributing to the establishment of the maternal: placental interface remain poorly understood. RESULTS: We characterized the endometrial gene expression profile during the peri-implantation stage of development by comparing two breeds that demonstrate very different reproductive efficiencies. We employed the porcine Affymetrix GeneChip® to assay the transcriptomic profiles of genes expressed in the uterine endometrium obtained from Meishan and Yorkshire gilts (n = 4 for each breed) on day 12 of gestation (M12 and Y12, respectively). Total of 17,076 probesets were identified as "present" in at least two arrays. A mixed model-based statistical analysis predicted a total of 2,656 (q < 0.1) transcripts as differentially expressed between Meishan and Yorkshire pigs. Eighteen differentially expressed transcripts of interest were validated by quantitative real-time PCR. Gene ontology (GO) annotation revealed that the known functions of the differentially expressed genes were involved in a series of important biological processes relevant to early pregnancy establishment in the pig. CONCLUSIONS: The results identified endometrial gene expression profiles of two breeds differing in litter size and identified candidate genes that are related to known physiological pathways related to reproductive prolificacy. These findings provide a deeper understanding of molecular pathways differing between two breeds at the critical peri-implantation stage of pregnancy, which can be utilized to better understand the events contributing to pregnancy establishment in the pig. Meishan and Yorkshire breeds endometirum were selected and RNA been extracted and hybridized to the Affymetrix microarray. A number of genes have been shown differently expressed on two breeds.

Project description:BACKGROUND: Litter size in pigs is a major factor affecting the profitability in the pig industry. The peri-implantation window in pigs is characterized by the coordinated interactions between the maternal uterine endometrium and the rapidly elongating conceptuses and represents a period of time during which a large percentage of the developing conceptuses are lost. However, the gene expression and regulatory networks in the endometrium contributing to the establishment of the maternal: placental interface remain poorly understood. RESULTS: We characterized the endometrial gene expression profile during the peri-implantation stage of development by comparing two breeds that demonstrate very different reproductive efficiencies. We employed the porcine Affymetrix GeneChip® to assay the transcriptomic profiles of genes expressed in the uterine endometrium obtained from Meishan and Yorkshire gilts (n = 4 for each breed) on day 12 of gestation (M12 and Y12, respectively). Total of 17,076 probesets were identified as "present" in at least two arrays. A mixed model-based statistical analysis predicted a total of 2,656 (q < 0.1) transcripts as differentially expressed between Meishan and Yorkshire pigs. Eighteen differentially expressed transcripts of interest were validated by quantitative real-time PCR. Gene ontology (GO) annotation revealed that the known functions of the differentially expressed genes were involved in a series of important biological processes relevant to early pregnancy establishment in the pig. CONCLUSIONS: The results identified endometrial gene expression profiles of two breeds differing in litter size and identified candidate genes that are related to known physiological pathways related to reproductive prolificacy. These findings provide a deeper understanding of molecular pathways differing between two breeds at the critical peri-implantation stage of pregnancy, which can be utilized to better understand the events contributing to pregnancy establishment in the pig.

Project description:Prolificacy related traits are of great economical interest in the pig industry. microRNAs (miRNAs) are post-transcriptional regulators of gene expression important for reproductive processes. In pigs, the roles of ovarian miRNAs during gestation remain unknown although the ovaries are essential during gestation. It has been hypothesised that ovarian miRNAs could participate during the porcine gestation and, moreover, they could influence the prolificacy levels of sows. The miRNA expression profile was compared in the ovaries of pregnant Iberian x Meishan F2 sows displaying extreme phenotypes regarding prolificacy levels defined as the number of embryos (NE) attached to the uterus at 30-32 days of gestation. miR-146a-5p and miR-142-3p were differentially expressed between high (NEM-bM-^IM-%13) and low (NEM-bM-^IM-$11) prolificacy sows. In silico functional analyses of the predicted mRNA targets for these miRNAs revealed that miR-146a-5p targets were mainly involved in the immune system response important for the establishment of the maternal-foetal tolerance, implantation and maintenance of pregnancy. On the other hand, miR-142-3p targets participated in different biological processes that would contribute to the homeostasis maintenance to ensure a correct functional development of the ovaries. miRNAs associated with prolificacy levels could regulate negatively, by a novel post-transcriptional mechanism, their predicted mRNA targets, PPM1K, TLR1 and CPEB2 which have been reported as differentially expressed in the ovaries of pregnant sows regarding the prolificacy levels. Furthermore, among predicted mRNA targets for miRNAs associated with prolificacy, four genes, differentially expressed in the ovaries of pregnant sows regarding prolificacy levels, (LRRK1, BAT1, CPEB2, CCL8) are proposed to be good candidate genes for litter size due to their location within confidence intervals for prolificacy QTL described previously. Overall, it is suggested that the up-regulation of miR-146a-5p and miR-142-3p in the ovaries of pregnant sows could help in the establishment of a uterine environment, which would favor the embryonic development. Total RNA was isolated from uterus of Iberian x Meishan F2 pregnant sows divided into two groups: High prolificacy sows (n=3) and Low prolificacy sows (n=3). RNA was labeled with the Cy3-like Hy3M-bM-^DM-" dye, mixed with a pool of RNA from the six samples labeled with the Cy5-like Hy5M-bM-^DM-" dye, and hybridized to two-color miRCURYM-bM-^DM-" arrays from ExiqonM-BM-..

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Gene expression profile of circRNA in spleen tissue of Meishan pigs at different time points

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