Gene Expression Profiles in Immature and In vitro matured bovine Oocytes

In cattle, almost all fully grown vesicle stage oocytes (GV) have the ability to resume meisos, develop to Metaphase II stage (MII), support fertilization and progress through the early embryonic cycles in vitro. Yet without intensive selection, the majority fail to develop to the blastocyst stage. Using the Affymetrix Bovine Genome Array, global mRNA expression analysis of immature (GV) and in vitro matured (IVM) bovine oocytes was carried out to characterize the transcriptome of the bovine oocyte and to identify the key pathways associated with oocyte meiotic maturation and developmental potential. Immature and in vitro matured bovine oocytes were collected for RNA extraction and hybridization on Affymetrix GeneChip Bovine Genome array. Careful removal of cumulus and selection of oocytes was carried out under the stereo microscope in order to examine the actual cumulus-free temporal oocyte gene expression profiles. Immature oocytes at time 0 h and in vitro matured oocytes at 24 h were collected for analysis.