نتایج جستجو برای: germ cells
تعداد نتایج: 1401216 فیلتر نتایج به سال:
The mesenchymal distal tip cell (DTC) provides the niche for Caenorhabditis elegans germline stem cells (GSCs). The DTC has a complex cellular architecture: its cell body caps the distal gonadal end and contacts germ cells extensively, but it also includes multiple cellular processes that extend along the germline tube and intercalate between germ cells. Here we use the lag-2 DTC promoter to dr...
In Drosophila, the sex of XX germ cells is determined by somatic signals. Whether sex-specific genes, however, are activated or repressed by somatic signals is not known. We have used mgm1, a germline-marker which is specifically expressed in male germ cells to analyze sex-specific gene expression of embryonic germ cells. We found that XX and XY germ cells that do not contact gonadal tissue can...
Approximately 20-25 primordial germ cells leave the endoderm between stages 38-41 and localize in the dorsal root of the mesentery by stage 43/44. At this time all the cells contain large quantities of yolk which is gradually resorbed. The cells begin dividing between stages 48-52. The number and size of the germ cells were measured in tadpoles between stages 48-54 of development. The results i...
In Drosophila, germ cell formation depends on inherited maternal factors localized in the posterior pole region of oocytes and early embryos, known as germ plasm. Here, we report that heterozygous cup mutant ovaries and embryos have reduced levels of Staufen (Stau), Oskar (Osk) and Vasa (Vas) proteins at the posterior pole. Moreover, we demonstrate that Cup interacts with Osk and Vas to ensure ...
Defining normal and malignant germ cell development is crucial for understanding the biology and behavior of germ cell tumors. Germ cell tumors show significant similarities with immature germ cells. Furthermore, treatment sensitivity of germ cell tumors reflects the intrinsic characteristics of the cell of origin, and their derivatives. The aim of this thesis was to identify factors involved i...
In Drosophila, germ cell survival and directionality of migration are controlled by two lipid phosphate phosphatases (LPP), wunen (wun) and wunen-2 (wun2). wun wun2 double mutant analysis reveals that the two genes, hereafter collectively called wunens, act redundantly in primordial germ cells. We find that wunens mediate germ cell-germ cell repulsion and that this repulsion is necessary for ge...
BACKGROUND Signaling mechanisms involved in early human germ cell development are largely unknown and believed to be similar to mouse germ cell development; however, there may be species specific differences. KIT ligand (KITL) and Bone morphogenetic protein 4 (BMP4) are necessary in mouse germ cell development and may play an important role in human germ cell development. METHODS KITL signali...
Shakespeare advises us that some men are born great, some achieve greatness, and some have greatness thrust upon them. So it is with germ cells. In Drosophila, the very first cells to be formed in the embryo, the pole cells, are germ cells whose descendants have no fate other than to give rise to gametes. In Caenorhabditis and in zebra fish, germ cell determinants present in the egg are asymmet...
THE origin of the germ-cells has been extensively investigated in both invertebrates and vertebrates. In invertebrates it has been traced to the early cleavage of the zygote, e.g. in such forms as Ascaris megalocephala (Boveri, 1887) and Sciara (Metz, 1938). Within the vertebrate group the cases in which primordial germ-cells have been detected in cleavage stages are very few. Eigenmann (1891) ...
mes-3 is one of four maternal-effect sterile genes that encode maternal components required for normal postembryonic development of the germ line in Caenorhabditis elegans. mes-3 mutant mothers produce sterile progeny, which contain few germ cells and no gametes. This terminal phenotype reflects two problems: reduced proliferation of the germ line and germ cell death. Both the appearance of the...
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