Identification of differential gene expression during porcine conceptus rapid trophoblastic elongation and attachment to uterine luminal epithelium

Abstract

Early embryonic development in the pig is characterized by a rapid elongation of the conceptus trophectoderm on days 11-12 of gestation. Initially, the conceptus trophoblast is morphologically rearranged from a 10-mm sphere into a tubular shape, transitioning into a thin filamentous form >150 mm in length in 2-3 h, followed by continued expansion within the uterine lumen for several days. Conceptus elongation is critical for establishing adequate placental surface area needed for embryo and fetal survival throughout gestation. The objective of this study was to characterize conceptus gene expression during trophoblastic elongation and the early attachment to the uterine endometrium on days 11-14 of gestation with the GeneChip Porcine Genome Array. In all, 3,759 different probe sets were statistically different in at least one comparison [spherical vs. tubular, spherical vs. day 12 filamentous (D12F), spherical vs. day 14 filamentous (D14F), tubular vs. D12F, tubular vs. D14F, and D12F vs. D14F]. When restricted to the spherical vs. D12F and D12F vs. D14F comparisons, 482 and 232 genes, respectively, were statistically different with greater than twofold change in expression. Utilization of k-means clustering, in addition to the Database for Annotation, Visualization, and Integrated Discovery (DAVID), identified genes of interest. Quantitative RT-PCR expression profiles for interferon-gamma (IFNG), heat shock protein 27 kDa (HSPB1), angiomotin, B-cell linker (BLNK), chemokine ligand 14 (CXCL14), parathyroid hormone-like hormone (PTHLH), and maspin were supportive of the GeneChip Porcine Genome Array data.

Implantation and Establishment of Pregnancy in the Pig

“…Although transcriptome profi ling identifi ed a number of genes that are up-or downregulated during this critical period of conceptus transformation, IL1B is the most abundantly expressed transcript during the time of tubular to fi lamentous transition for pig conceptuses (Ross et al 2009 ). Expression of IL1B during the period when pig conceptuses transition to fi lamentous morphology was fi rst described by Tuo et al ( 1996 ).…”

“…Although the dramatic increase in IL1B2 mRNA expression by pig conceptuses only occurs during the period of rapid elongation (day 11-12), IL1B2 protein is detectable in the uterine lumen from day 12 to 18 of gestation (Ross et al 2009 ). Differentiation of conceptus mesoderm ( Meso ) is evident after the 5 mm spherical conceptus stage when estrogen and IL1B2 production are fi rst detected ( f ).…”

“…Immediately following conceptus elongation and the rapid decline in IL1B2 gene expression, pig conceptuses express and secrete interferon gamma (INFG) and delta (INFD) between days 12 and 20 of gestation when there is a 567-fold increase in IFNG mRNA during the transition from spherical to day 14 fi lamentous conceptuses (La Bonnardière et al 1991 ;Cencic and La Bonnardière 2002 ;Ross et al 2009 ). Indeed, pig conceptuses are unique in secreting both type I and type II IFNs during the peri-implantation period of pregnancy.…”

A small set of extra-embryonic genes defines a new landmark for bovine embryo staging

“…On the other hand, one could search de novo for ovine, porcine or mouse predictive genes to appreciate the generic value of our strategy. Unfortunately, gene expression profiles reported so far on sheeps and pigs were conducted on whole elongating conceptuses (Cammas et al 2005, Ross et al 2009), which may confuse the analysis.…”

Amot Recognizes a Juxtanuclear Endocytic Recycling Compartment via a Novel Lipid Binding Domain

“…Amot was initially recognized for roles in the migration of endothelial cells (23)(24)(25). Although Amot expression is low in most differentiated epithelial cells (25,26), it is strongly up-regulated during epithelial migration programs during developmental processes, such as trophoblast extension (27) and anterior visceral endoderm formation (22,28). Amot is essential for this latter process because its genetic deletion in mice results in embryonic lethality from an inability of epithelial cells in the anterior visceral endoderm to migrate (28).…”