Identifying oocyte-expressed molecules essential for pre-implantation embryo development

Human embryonic stem cells (hESCs) have generated considerable excitement as a both a cellular model for human embryonic development, and a potential therapeutic tool to replace or repair damaged tissues.  Our lab uses hESCs to understanding the function of molecules that are expressed in common between hESCs and unfertilized oocytes obtained from the IVF clinic, with the goal to identify novel oocyte-expressed genes that regulate development of the preimplantation embryo.  In humans, oocytes regulate preimplantation embryo development by reprogramming both the oocyte and sperm nucleus to form a totipotent embryo following fertilization.  If implanted, this embryo is capable of developing into the next generation.   Recently, it has been shown in mice that removal of the oocyte nucleus and replacement with a somatic nucleus (Somatic cell nuclear transfer, SCNT) results in genomic reprogramming and formation of pluripotent embryonic stem cells. This experiment is yet to be fully proven using human oocytes.   The only human cell type that has the capacity to reprogram DNA is hESCs.   Therefore, we hypothesize that hESCs and oocytes must in part express unique reprogramming machinery, which is not found in any other somatic cell type.  As a result, identifying molecules expressed in common between human oocytes and hESCs and studying the function of these molecules using hESCs will enable the identification of this unique molecular program.