Transcriptome analysis of bovine uninucleated trophoblast cells (UTC) and Trophoblast Giant Cells (TGC)

In the bovine placenta, intimate fetomaternal contacts are confined to multiple discrete structures termed placentomes. In the placentomes, widely ramified fetal chorionic villi interdigitate with corresponding maternal caruncular crypts. The trophoblast covering the chorionic villi is composed of uninucleate trophoblast cells (UTCs) and binucleate trophoblast giant cells (TGCs). TGCs are weakly invasive and capable of migrating toward the caruncular epithelium where they eventually fuse with single epithelial cells to form short-living trinucleate fetomaternal hybrid cells. Thereby, molecules of fetal origin are transported into the maternal compartment. The loss of TGCs due to fetomaternal hybrid cell formation is compensated by differentiation of UTCs into TGCs. We performed a genome-wide gene expression study of virtually pure UTCs and TGCs to to identify genes which are associated with trophoblast cell differentiation Bovine placentomes were obtained from three pregnant cows from days 118 to 130 of gestation. UTCs and TGCs were isolated by an optimized fluorescence activated cell sorting (FACS) procedure. RNA was isolated and subjected to mRNA microarray analysis using Bovine Gene 1.0 ST Arrays (Affymetrix, St. Clara, CA, USA).