نتایج جستجو برای: spermatogonia cell
تعداد نتایج: 1684608 فیلتر نتایج به سال:
The purpose of the present study was to determine whether dark and pale type A spermatogonia (Ad and Ap, respectively) are mitotically active during prepubertal development and whether proliferation of these germ cells during this protracted phase of primate development occurs predominantly during infancy before gonadotropin secretion is arrested. Four neonate (1-2 days of age), four infant (4-...
The mammalian Cdkn2a (Ink4a-Arf) locus encodes two tumor suppressor proteins (p16(Ink4a) and p19(Arf)) that respectively enforce the anti-proliferative functions of the retinoblastoma protein (Rb) and the p53 transcription factor in response to oncogenic stress. Although p19(Arf) is not normally detected in tissues of young adult mice, a notable exception occurs in the male germ line, where Arf...
Background Infertility affects around 15% of couples, and male factors account for 50%. Cryptorchidism is one of the most common causes for azoospermia. Generation of functional spermatids from azoospermia patients is of unusual significance for treating male infertility. It has been recently reported by peers and us that human spermatogonial stem cells (SSCs) can be clearly identified and cult...
BACKGROUND Unilateral orchidectomy in monkeys increases spermatogenesis in the remaining testis in association with elevated follicle-stimulating hormone (FSH) secretion and testicular testosterone. The present study examined the relative importance of FSH and testosterone in driving the primate testis toward its spermatogenic ceiling. METHODS Adult male rhesus monkeys were treated with a gon...
BACKGROUND AND AIMS In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1...
ABSTRACT Heterochromatin-related epigenetic mechanisms, such as DNA methylation, facilitate pairing of homologous chromosomes during the meiotic prophase mammalian spermatogenesis. In pro-spermatogonia, de novo methylation plays a key role in completing and initiating division. However, maintenance regulation meiosis, especially adult, is not well understood. Here, we reveal that NP95 (also kno...
Murine spermatogonial stem cells: targeted transgene expression and purification in an active state.
A 400 bp fragment of the spermatogonia-specific Stra8 locus was sufficient to direct gene expression to the germinal stem cells in transgenic mice. A fractionation procedure was devised, based on immunomagnetic sorting of cells in which the promoter drives the expression of a surface functionally neutral protein tag. The purified cells expressed the known molecular markers of spermatogonia Rbm,...
Vaccinia-related kinase 1 (VRK1) is a crucial protein kinase for mitotic regulation. VRK1 is known to play a role in germ cell development, and its deficiency results in sterility. Here we describe that VRK1 is essential for the maintenance of spermatogonial stem cells. To determine whether VRK1 plays a role in these cells, we assessed the population size of undifferentiated spermatogonia. Flow...
In the absence of somatic cells, medium conditioned by the SNL fibroblast line (SNL-CM) is able to stimulate primary cultures of rat type-A single spermatogonia to develop into chains of aligned spermatogonia at the 8-, 16-, and 32-cell stages. By comparison, medium conditioned by an MSC-1 Sertoli cell line is ineffective. Glial cell line-derived neurotrophic factor (GDNF)-like molecules were i...
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