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Dudley Brian - - 2010
Stem cells are necessary to maintain tissue homeostasis and the microenvironment (a.k.a. the niche) surrounding these cells controls their ability to self-renew or differentiate. For many stem cell populations it remains unclear precisely what cells and signals comprise a niche. Here we identify a possible PGC niche in the mouse ...
Western Patrick S - - 2010
Mammalian germ cells are derived from the pluripotent epiblast and share features with pluripotent stem cells, including the expression of key genes that regulate developmental potency. The core genes Oct4, Sox2, and Nanog that regulate pluripotency in stem cells also perform important roles in regulating germ cell development and potentially ...
Bowles Josephine - - 2010
Mammalian germ cells do not determine their sexual fate based on their XX or XY chromosomal constitution. Instead, sexual fate is dependent on the gonadal environment in which they develop. In a fetal testis, germ cells commit to the spermatogenic programme of development during fetal life, although they do not ...
Chang Yu-Chen - - 2010
Centrosomal protein 55 (Cep55), located in the centrosome in interphase cells and recruited to the midbody during cytokinesis, is essential for completion of cell abscission. Northern blot previously showed that a high level of Cep55 is predominantly expressed in the testis. In the present study, we examined the spatial and ...
Saitou Mitinori - - 2010
The specification of germ cell fate in development initiates mechanisms essential for the perpetuation of genetic information across the generations. Recent studies in mice have shown that germ cell specification requires at least three key molecular/cellular events: repression of the somatic program, re-acquisition of potential pluripotency, and an ensuing genome-wide ...
Hermo Louis - - 2010
As germ cells divide and differentiate from spermatogonia to spermatozoa, they share a number of structural and functional features that are common to all generations of germ cells and these features are discussed herein. Germ cells are linked to one another by large intercellular bridges which serve to move molecules ...
Dyce Paul William - - 2010
The study of primordial germ cell development in vivo is hampered by their low numbers and inaccessibility. Recent research has shown the ability of embryonic and adult stem cells to differentiate into primordial germ cells and more mature gametes and this generation of germ cells in vitro may be an ...
Niu XuBo - - 2010
Three germ cell layers, the ectoderm, mesoderm and endoderm, are established during the gastrulation stage. All cell types in different organs and tissues are derived from these 3 germ cell layers at later stages. For example, skin epithelial cells and neuronal cells are derived from the ectoderm, while endothelial cells ...
Hermo Louis - - 2010
In the testis, cell adhesion and junctional molecules permit specific interactions and intracellular communication between germ and Sertoli cells and apposed Sertoli cells. Among the many adhesion family of proteins, NCAM, nectin and nectin-like, catenins, and cadherens will be discussed, along with gap junctions between germ and Sertoli cells and ...
Akiyama-Oda Yasuko - - 2010
The early embryo of the spider Achaearanea tepidariorum is emerging as a model for the simultaneous study of cell migration and pattern formation. A cell cluster internalized at the center of the radially symmetric germ disc expresses the evolutionarily conserved dorsal signal Decapentaplegic. This cell cluster migrates away from the ...
Hermo Louis - - 2010
Spermatogenesis, a study of germ cell development, is a long, orderly, and well-defined process occurring in seminiferous tubules of the testis. It is a temporal event whereby undifferentiated spermatogonial germ cells evolve into maturing spermatozoa over a period of several weeks. Spermatogenesis is characterized by three specific functional phases: proliferation, ...
Xu HongYan - - 2010
Fish, like many other animals, have two major cell lineages, namely the germline and soma. The germ-soma separation is one of the earliest events of embryonic development. Germ cells can be specifically labeled and isolated for culture and transplantation, providing tools for reproduction of endangered species in close relatives, such ...
Nakamura Yoshiaki - - 2010
We report a novel technique for almost complete replacement of the recipient germline with donor germ cells in the chicken. Busulfan solubilized in a sustained-release emulsion was injected into the yolk of fertile eggs before incubation. A dose of 100 microg was found to provide the best outcome in terms ...
Yamada Kyoko - - 2010
AZFc deletions are associated with variable testicular histology ranging from the Sertoli cell only to spermatogenic arrest and hypospermatogenesis. Such variable phenotypes may be explained by progressive germ cell regression over time. Increased apoptosis is likely responsible for progressive regression of spermatogenic potential. This study evaluated germ cell apoptosis as ...
Yoshizaki Goro - - 2010
The sexual plasticity of fish gonads declines after the sex differentiation period; however, information about the plasticity of the germ cells themselves after sex differentiation is limited. Using rainbow trout (Oncorhynchus mykiss), we recently established a novel germ cell transplantation system that provides a unique platform with which to dissect ...
Huang Peng - - 2010
Recent studies have demonstrated that mesenchymal stem cells could differentiate into germ cells under appropriate conditions. We sought to determine whether human umbilical cord Wharton's jelly-derived mesenchymal stem cells (HUMSCs) could form germ cells in vitro. HUMSCs were induced to differentiate into germ cells in all-trans retinoic acid, testosterone and ...
Chuva de Sousa Lopes Susana M - - 2010
Mammalian germ cells are powerful cells, the only ones that transmit information to the next generation ensuring the continuation of the species. But "with great power, comes great responsibility", meaning that germ cells are only a few steps away from turning carcinogenic. Despite recent advances little is known about germ ...
Tang Fuchou - - 2010
Germ cells are the only immortal cells in a mammalian organism. Here, I review recent progress in the research on the role of small non-coding RNAs - namely microRNAs (miRNAs), endogenous siRNAs (endo-siRNAs), and piwi-interacting RNAs (piRNAs) - in the development of mammalian germ cells. Two key functions of small ...
Yu Lin - - 2010
Reduction of Nanos activity causes germ line stem cell failure in the Drosophila ovary. Only a few cysts with Vasa-positive (green) differentiating germ line cells remain. The adducin-like molecule Hts, which marks membranes, is red and DNA is blue. See the article by Yu et al. in this issue.
Yu Lin - - 2010
The translational repressor Nanos is required in the germ line stem cells of the Drosophila ovary to maintain their capacity for self-renewal. Following division of the stem cells, Nanos is inhibited in the daughters that differentiate into cysts and ultimately become mature oocytes. The control of Nanos activity is thus ...
Ollinger Rupert R MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh EH4 2XU, UK. - - 2010
In mammals, germ cells derive from the pluripotent cells that are present early in embryogenesis, and then differentiate into male sperm or female eggs as development proceeds. Fusion between an egg and a sperm at fertilization allows genetic information from both parents to be transmitted to the next generation, and ...
Gruber Michaela M Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, - - 2010
Spermatogenesis, a process involving the differentiation of spermatogonial stem cells into mature spermatozoa, takes place throughout masculine life. A complex system in the testis, including endocrine signaling, physical interactions between germ and somatic cells, spermatocyte meiosis, and timely release of spermatozoa, controls this cycle. We demonstrate herein that decreased O(2) ...
Iwamori Tokuko - - 2010
In somatic cells, abscission, the physical separation of daughter cells at the completion of cytokinesis, requires CEP55, ALIX, and TSG101. In contrast, cytokinesis is arrested prior to abscission in differentiating male germ cells that are interconnected by TEX14-positive intercellular bridges. We have previously shown that targeted deletion of TEX14 disrupts ...
Ruwanpura Saleela M - - 2010
Over the past five decades, intense research using various animal models, innovative technologies notably genetically modified mice and wider use of stereological methods, unique agents to modulate hormones, genomic and proteomic techniques, have identified the cellular sites of spermatogenesis, that are regulated by FSH and testosterone. It has been established ...
Han Jianyong - - 2010
Induced pluripotent stem (iPS) cells can be obtained by the introduction of defined factors into somatic cells. The combination of Oct4 (also known as Pou5f1), Sox2 and Klf4 (which we term OSK) constitutes the minimal requirement for generating iPS cells from mouse embryonic fibroblasts. These cells are thought to resemble ...
Pacchiarotti Jason - - 2010
General belief in reproductive biology is that in most mammals female germ line stem cells are differentiated to primary oocytes during fetal development and oogenesis starts from a pool of primordial follicles after birth. This idea has been challenged previously by using follicle kinetics studies and demonstration of mitotically active ...
Berndtson William E - - 2010
The typical levels of inherent variability among untreated sexually mature rodents, rabbits, or men were determined for several endpoints used to characterize spermatogenesis. The latter included germ cell:germ cell and germ cell:Sertoli cell ratios, the frequency of specific stages of the cycle of the seminiferous epithelium, and the appearance of ...
Mithraprabhu Sridurga - - 2010
The transforming growth factor beta superfamily ligand activin A controls juvenile testis growth by stimulating Sertoli cell proliferation. Testicular levels are highest in the first postnatal week, when Sertoli cells are proliferating and spermatogonial stem cells first form. Levels decrease sharply as Sertoli cell proliferation ceases and spermatogenic differentiation begins. ...
de Sousa Lopes Susana M Chuva - - 2010
In mammals, germ cells undergo a long journey from specification until sexual maturation. During this journey, which takes place during the entire life cycle of mammals, the germ cells dynamically change their morphology, their expression profile and also the number and character of their cellular bodies. The focus of this ...
Guan W - - 2010
Embryonic germ (EG) cells derived from primordial germ cells are undifferentiated and pluripotent stem cells. In our study, primordial germ cells isolated from the genital ridges of Beijing duck (Anas domestica) embryo at stage 28 were co-cultured with mice embryonic fibroblasts. Duck EG cells grew with a high nuclear:cytoplasm ratio ...
Wu Yanqun - - 2010
Although the pluripotent and proliferative capacity of embryonic germ (EG) cells is thought to be equivalent to that of embryonic stem (ES) cells, there has been far less attention focused on the potential use of EG cells for applications in developing novel strategies of tissue transplantation in the treatment of ...
Hou Wugang - - 2010
OBJECTIVES: To examine the expression of N-Myc downstream regulated gene 2 (NDRG2) in the cryptorchid testes and its potential association with germ cell apoptosis in a rat model of cryptorchidism. METHODS: Groups of pubertal Sprague-Dawley rats were subjected to surgical procedure for the induction of experimental unilateral cryptorchidism. The weight ...
Miles Denise C - - 2010
During mouse embryonic development germ cells proliferate extensively until they commit to the male or female pathway and arrest in mitosis or meiosis respectively. Whilst the transition of female germ cells exiting the mitotic cell cycle and entering meiosis is well defined histologically, the essential cell cycle proteins involved in ...
Yamano Noriko - - 2010
Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific ...
Schaniel Christoph - - 2010
Embryonic stem cells (ESCs) have the ability to expand indefinitely in vitro and give rise to cells of all three germ layers as well as germ cells. For these reasons, ESCs hold great promise for biomedicine. In order to harness the potential of pluripotent cells, it is necessary to first ...
Ray B - - 2010
AIM: To investigate whether cyclophosphamide interferes with ovarian folliculogenesis. METHODS: In this experiment, pregnant rats (n=12) were randomly assigned into two groups, control group (n=6) and cyclophosphamide treatment group (n=6). In the cyclophosphamide treatment group cyclophosphamide was injected intraperitoneally from day 10 of gestation till 20th day, at 2 mg/kg ...
Jung Jin Gyoung - - 2010
We recently developed bimodal germline chimera production approaches by transfer of primordial germ cells (PGCs) or embryonic germ cells (EGCs) into embryos and by transplantation of spermatogonial stem cells (SSCs) or germline stem cells (GSCs) into adult testes. This study was undertaken to investigate the reversible developmental unipotency of chicken ...
Kugler Jan-Michael - - 2010
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 ...
Kobayashi Tohru - - 2010
To clarify the sexually dimorphic mechanisms of gonadal sex differentiation, we established an in vitro culture system for gonadal sex differentiation using the teleost fish Oreochromis niloticus. In vivo, the entry of germ cells into meiosis occurs around 35 days after hatching (dah) in XX gonads, whereas in XY gonads, ...
Piprek Rafa? P - - 2010
The aim of this study was to investigate consecutive stages of gonadal development of the yellow-bellied toad (Bombina variegata) with particular emphasis on the origin of somatic and germ cell lineages as well as the timing of gonial cell migration. Changes in gonadal basal lamina distribution helped to explain the ...
Liu Chia-Feng - - 2010
Female germ cells are essential for organogenesis of the ovary; without them, ovarian follicles do not form and functional and structural characteristics of the ovary are lost. We and others showed previously that when either Wnt4 or beta-catenin was inactivated in the fetal ovary, female germ cells underwent degeneration. In ...
Freund C - - 2010
One of the recent breakthroughs in stem cell research has been the reprogramming of human somatic cells to an embryonic stem cell (ESC)-like state (induced pluripotent stem cells, iPS cells). Similar to ESCs, iPS cells can differentiate into derivatives of the three germ layers, for example cardiomyocytes, pancreatic cells or ...
Suzuki Hitomi - - 2010
The regulation of gene expression via a 3' untranslated region (UTR) plays essential roles in the discrimination of the germ cell lineage from somatic cells during embryogenesis. This is fundamental to the continuation of a species. Mouse NANOS3 is an essential protein required for the germ cell maintenance and is ...
Richardson Brian E - - 2010
The regulated migration of cells is essential for development and tissue homeostasis, and aberrant cell migration can lead to an impaired immune response and the progression of cancer. Primordial germ cells (PGCs), precursors to sperm and eggs, have to migrate across the embryo to reach somatic gonadal precursors, where they ...
Ko Kinarm - - 2010
Embryonic stem cells (ESCs) have the potential to differentiate into cells of all tissue types, as demonstrated by their capability to contribute to the development of all germ layers in chimeras and to form teratomas. Of interest, however, is the lack of evidence of gametogenic gonadal tissues within teratomas, such ...
Seisenberger Stefanie - - 2010
The evolutionary success of retrotransposable elements is reflected by their abundance in mammalian genomes. To restrict their further advance, a number of defence mechanisms have been put in place by the host. These seem to be particularly effective in the germ line while somatic lineages might be more permissive to ...
Crum Christopher P CP Division of Women's and Perinatal Pathology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. - - 2010
The p53homolog p63has emerged as a gene with an enormously complex function that is distinct from that of p53. It encodes two distinct transcript isoforms that have a dramatic impact on replenishment of cutaneous epithelial stem cells and on ovarian germ cell survival. However, although these two fundamental roles of ...
Tilgner Katarzyna K North East Stem Cell Institute, Newcastle University, International Centre for Life, NE1 3BZ, United - - 2010
The isolation of significant numbers of human primordial germ cells at several developmental stages is important for investigations of the mechanisms by which they are able to undergo epigenetic reprogramming. Only small numbers of these cells can be obtained from embryos of appropriate developmental stages, so the differentiation of human ...
Ewen Katherine A - - 2010
Primordial germ cells (PGCs) are embryonic progenitors for the gametes. In the gastrulating mouse embryo, a small group of cells begin expressing a unique set of genes and so commit to the germline. Over the next 3-5 days, these PGCs migrate anteriorly and increase rapidly in number via mitotic division ...
Brownfield Lynette - - 2009
The production of two functional sperm cells within each male gametophyte is essential for double fertilization in flowering plants and involves a single mitotic division of the male germ cell and cell specification to produce functional gametes. Several proteins that are important regulators of male germ cell division have been ...
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