A two-dimensional electrophoresis reference map for the bovine placenta during late pregnancy.

An understanding of bovine placental gene expression is essential for the study of animal reproductive physiology. Recent reports have found that placental abnormalities occur frequently in cloned bovines and mice. However, the molecular mechanisms underlying bovine placenta function remain unclear. Here, we present a preliminary description of the bovine placenta proteome. Proteins within the isoelectric point ranging from 4.0 to 7.0 and 6.0 to 9.0 were analyzed separately using 2-DE, using three replicates of bovine placenta. Approximately 2000 spots were detected in a placental 2-D gel stained with Coomassie blue. Subsequent excision of 380 spots from gels and MALDI-TOF MS analysis allowed the identification of 273 proteins. Our results revealed the composite profiles of key proteins in the bovine placenta during late pregnancy. These protein profiles will shed light on placental function during pregnancy and assist with functional analysis of the proteins.