Epigenetics for Germline Development
In the development of multicellular organisms, the genome of a single fertilized oocyte generates diverse cell types with distinct gene expression profiles. Distinct gene expression profile in each cell is established by epigenetic mechanisms including DNA methylation and histone tail modifications, which are often mitotically heritable. In terminally differentiated cells, epigenetic information is relatively fixed, resulting in the loss of differentiation potential. In contrast, germline cells can reprogram their epigenetic information in order to acquire cellular totipotency and prevent the accumulation of epigenetic mutation through the generation. A Major goal of our research is to elucidate and reconstitute epigenetic mechanisms ensuring cellular totipotency. We focused on genome-wide epigenetic reprogramming in primordial germ cell (PGCs), which are the orign of both sperm and oocyte, in mice. We have previously shown that PGCs erase genome-wide methylation and H3K9me2 in their development. Now we try to elucidate and reconstitute epigenetic mechanisms in PGCs using by in vitro differentiation system of germ cells from embryonic stem cells.