We previously reported that primordial germ cells (PGCs) in mice erase genome-wide DNA methylation and histone H3 lysine9 dimethylation (H3K9me2), and instead acquire high levels of tri-methylation of H3K27 (H3K27me3) during their migration, a process that might be crucial for the re-establishment of potential totipotency in the germline. We here explored a cellular dynamics associated with thi...

Germ-line stem cells (GSCs) are maintained by the somatic microenvironment, or GSC niche, which ensures that GSCs can both self-renew and produce functional gametes. However, it remains unclear how the proper niche size and location are regulated within the developing gonads. In the Drosophila testis, the hub cells that form the GSC niche are derived from a subset of somatic gonadal precursors ...

In all multicellular organisms, germ cells originating from a fertilized egg have the highly specialized role of transmitting genetic information to the next generation. In many animal species, the establishment of the germ cell lineage is regulated by the maternally inherited germplasm. In mammals, however, germline determination is not based on the unequal distribution of maternal determinant...

We have demonstrated that quail PGCs possess a characteristic heterochromatin nuclear marker demonstrable already at stage 6 H & H with Feulgen staining. Chimaeras of stage-XIII E. G & K chick epiblast and quail hypoblast and vice versa have been made. The chimaeras were incubated up to stage 7-8 H & H and checked histologically with Feulgen staining for the presence of the heterochromatin mark...

In order to sustain lifelong production of gametes, many animals have evolved a stem cell-based gametogenic program. In the Drosophila ovary, germline stem cells (GSCs) arise from a pool of primordial germ cells (PGCs) that remain undifferentiated even after gametogenesis has initiated. The decision of PGCs to differentiate or remain undifferentiated is regulated by somatic stromal cells: speci...

The genome-wide depletion of 5-methylcytosines (5meCs) caused by passive dilution through DNA synthesis without daughter strand methylation and active enzymatic processes resulting in replacement of 5meCs with unmethylated cytosines is a hallmark of primordial germ cells (PGCs). Although recent studies have shown that in vitro differentiation of pluripotent stem cells (PSCs) to PGC-like cells (...

Primordial germ cells (PGCs) and preimplantation embryos undergo epigenetic reprogramming, which includes comprehensive DNA demethylation. We found that PRMT5, an arginine methyltransferase, translocates from the cytoplasm to the nucleus during this process. Here we show that conditional loss of PRMT5 in early PGCs causes complete male and female sterility, preceded by the upregulation of LINE1...

The signals directing primordial germ cell (PGC) migration in vertebrates are largely unknown. We demonstrate that sdf-1 mRNA is expressed in locations where PGCs are found and toward which they migrate in wild-type as well as in mutant embryos in which PGC migration is abnormal. Knocking down SDF-1 or its receptor CXCR4 results in severe defects in PGC migration. Specifically, PGCs that do not...

Primordial germ cells (PGCs), the embryonic precursors of the gametes of the adult animal, can give rise to two types of pluripotent stem cells. In vivo, PGCs can give rise to embryonal carcinoma cells, the pluripotent stem cells of testicular tumors. Cultured PGCs exposed to a specific cocktail of growth factors give rise to embryonic germ cells, pluripotent stem cells that can contribute to a...

In mammalian primordial germ cells (PGCs), DNA demethylation is indispensible for parental imprint erasure, which is a reprogramming process essential for normal developmental potential. Thus, it is important to elucidate how DNA demethylation occurs in each imprinted region in PGCs and to determine which DNA demethylation pathway, passive or active, essentially contributes to the erasure of th...