genetic and epigenetic landscape of germline stem cells

elucidating the critical epigenetics events involved in differentiation and reprogramming of cells to primordial germ cells (pgcs) is among the interesting issues in stem cell research. here, i will talk about critical transcription factors and global hypomethylation in development of germ cells. evidence strongly suggests that the earliest pgcs emerging in the e7.25 mouse embryo epiblast have a highly methylated genome, and high level of h3k9me2 in chromatin but during development, genome demethylated and patterns of histone codes changes dramatically. we designed a polycistroniclentiviral vector and overexpressed stella, oct4 and nanos2 simultaneously in transduced cells; increasing level of prdm14, nanog and decreasing of g9a expression is an interesting finding which might be considered as a primary step of reprogramming toward germline progenitor cells, here we propose decreasing h3k9me2 level as a consequence of g9a down regulation is a critical step which facilitated transition to different stemness state through creating a new epigenetic memory for the early germ cells.   keywords: epigenetic, hypomethylation, germ line stem cells, polycistroniclentiviral vector.