New molecular markers involved in immune system homeostasis and hemopoietic organ development are differentially regulated during oocytes in vitro maturation

The growth and maturation of the oocyte is a dynamic process which requires a variable supply of hormones, growth factors and energy. These needs are met partially by the surrounding somatic cells and the cumulus-oocyte complex, which communicate bi-directionally via gap junctions. Identifying and analyzing protein expression in the oocyte can provide insight in its development and growth. Further, like bone marrow stem cells, if relevant marker genes are found in oocytes, there is a potential for the oocyte to be manipulated into becoming hemopoietic stem cells. In this study, porcine oocytes were isolated and subjected to microarray analysis to compare the oocyte gene expression in vivo and in vitro maturation (IVM). Genes identified belonged to both ‘hemopoietic or lymphoid organ development’(GO:0048534) and ‘immune system development’ (GO:0002520), and the markers can be used to identify several activities such as cell migration, neurogenesis and proliferation. The following are the identified genes and all were downregulated after IVM to varying degrees: ID2, VEGFA, TGFBR3, INHBA, CDK6, BCL11A, MYO1E, ITGB1, EGR1, NOTCH2, SPTA1, KIT and TPD52. Our results should provide new markers to further investigate oocyte development and growth regulation.

Running title: Markers of hemopoietic organ development