Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic nuclei that inherit this "germ plasm" acquire PGC fate. In contrast, historical studies of basally branching insects (Hemimetabola) suggest that a maternal requirement for g...

Germ cells occupy a unique position in animal reproduction, development, and evolution. In sexually reproducing animals, only they can produce gametes and contribute genetically to subsequent generations. Nonetheless, germ line specification during embryogenesis is conceptually the same as the specification of any somatic cell type: germ cells must activate a specific gene regulatory network in...

Caenorhabditis elegans germ-line proliferation is controlled by an inductive interaction between the somatic distal tip cell and the germ line. GLP-1, a member of the Notch family of transmembrane receptors, is required continuously in the germ line to transduce the proliferative signal. In the absence of GLP-1, all proliferative germ cells exit the mitotic cell cycle and enter meiotic prophase...

Drosophila oogenesis is especially well suited for studying stem cell biology, cellular differentiation, and morphogenesis. The small modifier protein ubiquitin regulates many cellular pathways. Ubiquitin is conjugated to target proteins by a diverse class of enzymes called ubiquitin E3 ligases. Here we characterize the requirement of Cul-5, a key component of a subgroup of Cullin-RING-type ubi...

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...

Alternative splicing of CREB (cAMP response element binding protein) and CREM (cAMP response element modulator) mRNAs in separated pachytene spermatocyte, round spermatid, and elongated spermatid fractions and the germ cell-derived immortalized cell line GC-2spd(ts) was studied by reverse transcription polymerase chain reaction (RT-PCR). Both primary germ cells and the GC-2spd(ts) cell line exp...

The retinoblastoma tumor suppressor gene Rb is essential for maintaining the quiescence and for regulating the differentiation of somatic stem cells. Inactivation of Rb in somatic stem cells typically leads to their overexpansion, often followed by increased apoptosis, defective terminal differentiation, and tumor formation. However, Rb's roles in germ-line stem cells have not been explored. We...