Combined analysis of transcriptome studies of bovine endometrium during the preimplantation phase and comparison to results from ovine and porcine preimplantation endometrium

Transcriptome studies of the bovine endometrium during early pregnancy and during the estrous cycle have been performed using DNA microarrays and RNA sequencing to identify genes associated with establishment and maintenance of pregnancy. The results of these studies are reviewed and the identified differentially expressed genes (DEG) are compared to define the overlaps between studies and technical platforms. Good overlaps were found for upregulated genes between different days of the preimplantation phase and between microarrays and RNA-Seq. In contrast, overlaps for downregulated genes were clearly lower between days but also between platforms. Possible causes are discussed. All DEG of the analyzed studies were summarized and a combined functional annotation analysis was performed. Gene expression of selected genes found as important for maternal recognition of pregnancy and implantation in sheep was compared between bovine and ovine endometrium. Furthermore, DEG in bovine endometrium were compared to DEG found in porcine endometrium on Day 14 of pregnancy, revealing significant similarities in differential endometrial gene expression in cattle and pigs.