Primordial Germ Cell Precursors (Epb)

The pluripotent proximal epiblast cells begin to express Ifitm3 and acquire the ability to form PGCs in response to signals from the extraembryonic tissues, although only a small minority of them become germ cells. At E6.2, about six Ifitm3+ cells in the prospective posterior proximal site of the embryo and directly in contact with the overlying extraembryonic ectoderm begin to show expression of Prdm1.