共查询到20条相似文献，搜索用时 15 毫秒
1.
Migration and differentiation of cerebral cortical neurons after transplantation into the brains of ferrets 总被引：4，自引：0，他引：4
S K McConnell 《Science (New York, N.Y.)》1985,229(4719):1268-1271
Cells from the cerebral proliferative zones of newborn ferrets were labeled with tritiated thymidine and a fluorescent dye and were transplanted as a single-cell suspension into the occipital region of newborn ferrets. The transplanted cells became thoroughly integrated into the host environment: many cells migrated through the intermediate zone and into the cortical plate, where they developed as pyramidal neurons. Other transplanted cells came to resemble glial cells. After 1 to 2 months most transplanted neurons had taken up residence in layer 2 + 3, the normal destination of neurons generated on postnatal days 1 and 2. Thus the sequence of morphological differentiation and the eventual laminar position of the isochronically transplanted neurons closely paralleled that of their normal host counterparts. 相似文献
2.
During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells, tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. Clonal analysis and fate mapping of single, identified cells show that tracheal system remodeling at metamorphosis involves a classical imaginal cell population and a population of differentiated, functional larval tracheal cells that reenter the cell cycle and regain developmental potency. In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling. Thus, Drosophila pupal/adult tissue progenitors can arise both by early allocation of multipotent cells and late return of differentiated cells to a multipotent state, even within a single tissue. 相似文献
3.
4.
Foxg1 suppresses early cortical cell fate 总被引：1，自引：0，他引：1
5.
The relation between terminal mitosis and the events that determine the developmental fate of embryonic precursor cells is not well understood. This relation has now been investigated with [3H]thymidine autoradiography to determine the time of cell birth and with a culture system that allows the testing of the developmental potential of cells isolated from the chick embryo retina. Contrary to the situation in vivo, where neuronal differentiation always precedes photoreceptor differentiation, photoreceptor differentiation occurs prematurely and precedes neuronal differentiation when precursor cells are isolated from the retina at early embryonic stages. Thus, cells born by embryonic day 5 (ED-5) give rise predominantly to photoreceptors when isolated for culture on ED-6 but develop mainly as neurons when isolated on ED-8. This suggests that retinal precursor cells retain after terminal mitosis the capacity to develop either as neurons or as photoreceptors. Moreover, photoreceptor differentiation appears to represent a constitutive or "default" pathway that precursor cells follow in the absence of neuron-inducing signals. 相似文献
6.
Electrical coupling: low resistance junctions between mitotic and interphase fibroblasts in tissue culture 总被引：7，自引：0，他引：7
Dividing cells of chick embryonic fibroblasts and of mouse embryonic fibroblasts (3T3) in tissue culture are electrically coupled to their interphase neighbors. Recordings from many such cells suggest that this coupling persists throughout the division cycle of the mitotic cell. 相似文献
7.
Lhx2 maintains stem cell character in hair follicles 总被引：1，自引：0，他引：1
8.
Specification of germ cells in mice occurs relatively late in embryonic development. It is initiated by signals that induce expression of Blimp1, a key regulator of the germ cell, in a few epiblast cells of early postimplantation embryos. Blimp1 represses the incipient somatic program in these cells and promotes progression toward the germ cell fate. Blimp1 may also have a role in the maintenance of early germ cell characteristics by ensuring their escape from the somatic fate as well as possible reversion to pluripotent stem cells. 相似文献
9.
Sex determination in the Drosophila germ line is regulated by both the sex of the surrounding soma and cell-autonomous cues. How primordial germ cells (PGCs) initiate sexual development via cell-autonomous mechanisms is unclear. Here, we demonstrate that, in Drosophila, the Sex lethal (Sxl) gene acts autonomously in PGCs to induce female development. Sxl is transiently expressed in PGCs during their migration to the gonads; this expression, which was detected only in XX PGCs, is necessary for PGCs to assume a female fate. Ectopic expression of Sxl in XY PGCs was sufficient to induce them to enter oogenesis and produce functional eggs when transplanted into an XX host. Our data provide powerful evidence that Sxl initiates female germline fate during sexual development. 相似文献
10.
目的:探讨小鼠胚胎中脑分离神经干细胞的体外培养方法,以获取高纯度的神经干细胞,为神经干细胞的深入研究提供试验材料。方法:无菌条件下分离孕12~13 d小鼠胚胎中脑曲,制成单细胞悬液,碱性成纤维生长因子(bFGF)和B27存在的培养基中培养扩增,通过免疫细胞化学染色鉴定神经干细胞及子代细胞的分化方向,流式细胞术检测TH阳性神经元比例。结果:培养的部分细胞体外分裂增殖,同时表达神经干细胞特异性抗原nestin,并向神经细胞和胶质细胞分化并经流式细胞仪检测自然分化为多巴胺能神经元的比例为3.25%。结论:小鼠胚脑中脑存在具有多分化潜能的神经干细胞,它们能在体外稳定培养、传代和分化。 相似文献
11.
Transforming growth factor-beta (TGF-beta) and TGF-beta-related proteins, such as the bone morphogenetic proteins, have emerged as key regulators of stem cell renewal and differentiation. These proteins have disparate roles in regulating the biology of embryonic stem cells and tumor suppression, and they help define the selection of cell fate and the progression of differentiation along a lineage. Here we illustrate their roles in embryonic stem cells and in the differentiation of neural, hematopoietic, mesenchymal, and gastrointestinal epithelial stem cells. 相似文献
12.
Okita K Nakagawa M Hyenjong H Ichisaka T Yamanaka S 《Science (New York, N.Y.)》2008,322(5903):949-953
Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by introducing Oct3/4 and Sox2 with either Klf4 and c-Myc or Nanog and Lin28 using retroviruses or lentiviruses. Patient-specific iPS cells could be useful in drug discovery and regenerative medicine. However, viral integration into the host genome increases the risk of tumorigenicity. Here, we report the generation of mouse iPS cells without viral vectors. Repeated transfection of two expression plasmids, one containing the complementary DNAs (cDNAs) of Oct3/4, Sox2, and Klf4 and the other containing the c-Myc cDNA, into mouse embryonic fibroblasts resulted in iPS cells without evidence of plasmid integration, which produced teratomas when transplanted into mice and contributed to adult chimeras. The production of virus-free iPS cells, albeit from embryonic fibroblasts, addresses a critical safety concern for potential use of iPS cells in regenerative medicine. 相似文献
13.
Out of Eden: stem cells and their niches 总被引：2，自引：0，他引：2
Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. Both intrinsic and extrinsic signals regulate stem cell fate and some of these signals have now been identified. Certain aspects of the stem cell microenvironment, or niche, are conserved between tissues, and this can be exploited in the application of stem cells to tissue replacement therapy. 相似文献
14.
Famulski JK Trivedi N Howell D Yang Y Tong Y Gilbertson R Solecki DJ 《Science (New York, N.Y.)》2010,330(6012):1834-1838
The brain's circuitry is established by directed migration and synaptogenesis of neurons during development. Although neurons mature and migrate in specific patterns, little is known about how neurons exit their germinal zone niche. We found that cerebellar granule neuron germinal zone exit is regulated by proteasomal degradation of Pard3A by the Seven in Absentia homolog (Siah) E3 ubiquitin ligase. Pard3A gain of function and Siah loss of function induce precocious radial migration. Time-lapse imaging using a probe to measure neuronal cell contact reveals that Pard3A promotes adhesive interactions needed for germinal zone exit by recruiting the epithelial tight junction adhesion molecule C to the neuronal cell surface. Our findings define a Siah-Pard3A signaling pathway that controls adhesion-dependent exit of neuronal progenitors or immature neurons from a germinal zone niche. 相似文献
15.
Cell recognition during neuronal development 总被引：20，自引：0，他引：20
C S Goodman M J Bastiani C Q Doe S du Lac S L Helfand J Y Kuwada J B Thomas 《Science (New York, N.Y.)》1984,225(4668):1271-1279
Insect embryos, with their relatively simple nervous systems, provide a model system with which to study the cellular and molecular mechanisms underlying cell recognition during neuronal development. Such an approach can take advantage of the accessible cells of the grasshopper embryo and the accessible genes of Drosophila. The growth cones of identified neurons express selective affinities for specific axonal surfaces; such specificities give rise to the stereotyped patterns of selective fasciculation common to both species. These and other results suggest that early in development cell lineage and cell interactions lead to the differential expression of cell recognition molecules on the surfaces of small subsets of embryonic neurons whose axons selectively fasciculate with one another. Monoclonal antibodies reveal surface molecules in the Drosophila embryo whose expression correlates with this prediction. It should now be possible to isolate the genes encoding these potential cell recognition molecules and to test their function through the use of molecular genetic approaches in Drosophila. 相似文献
16.
水稻花培获得大群体健壮绿苗的研究 总被引：1，自引：0，他引：1
通过使用混合激素诱发籼稻871015、871109花粉愈伤形成胚性细胞;对籼稻花粉胚性细胞团和粳稻绿芽丛进行分割培养,快速繁育大群体绿苗获得成功。籼稻两个组合的8块胚性细胞团,在两个月内经3—5次切割培养获得绿苗12690株;粳稻花培绿芽丛仅经一次分割培养后的净增绿苗率127.2%,大幅度地提高了水稻花药培养再生绿苗率。分割培养的再生苗,健壮的形成特征:苗粗、浓绿、根多、洁白。良好的生理素质:发根力强,平均每棵试管苗多增根1.8条,根长度增长168.4%;平均每棵再生苗鲜重和干重分别增加0.29克和0.175毫克。 相似文献
17.
Specification of cerebral cortical areas 总被引：131，自引：0，他引：131
P Rakic 《Science (New York, N.Y.)》1988,241(4862):170-176
How the immense population of neurons that constitute the human cerebral neocortex is generated from progenitors lining the cerebral ventricle and then distributed to appropriate layers of distinctive cytoarchitectonic areas can be explained by the radial unit hypothesis. According to this hypothesis, the ependymal layer of the embryonic cerebral ventricle consists of proliferative units that provide a proto-map of prospective cytoarchitectonic areas. The output of the proliferative units is translated via glial guides to the expanding cortex in the form of ontogenetic columns, whose final number for each area can be modified through interaction with afferent input. Data obtained through various advanced neurobiological techniques, including electron microscopy, immunocytochemistry, [3H]thymidine and receptor autoradiography, retrovirus gene transfer, neural transplants, and surgical or genetic manipulation of cortical development, furnish new details about the kinetics of cell proliferation, their lineage relationships, and phenotypic expression that favor this hypothesis. The radial unit model provides a framework for understanding cerebral evolution, epigenetic regulation of the parcellation of cytoarchitectonic areas, and insight into the pathogenesis of certain cortical disorders in humans. 相似文献
18.
SJ Franco C Gil-Sanz I Martinez-Garay A Espinosa SR Harkins-Perry C Ramos U Müller 《Science (New York, N.Y.)》2012,337(6095):746-749
During development of the mammalian cerebral cortex, radial glial cells (RGCs) generate layer-specific subtypes of excitatory neurons in a defined temporal sequence, in which lower-layer neurons are formed before upper-layer neurons. It has been proposed that neuronal subtype fate is determined by birthdate through progressive restriction of the neurogenic potential of a common RGC progenitor. Here, we demonstrate that the murine cerebral cortex contains RGC sublineages with distinct fate potentials. Using in vivo genetic fate mapping and in vitro clonal analysis, we identified an RGC lineage that is intrinsically specified to generate only upper-layer neurons, independently of niche and birthdate. Because upper cortical layers were expanded during primate evolution, amplification of this RGC pool may have facilitated human brain evolution. 相似文献
19.
Mosaic organization of neural stem cells in the adult brain 总被引：2，自引：0，他引：2
The in vivo potential of neural stem cells in the postnatal mouse brain is not known, but because they produce many different types of neurons, they must be either very versatile or very diverse. By specifically targeting stem cells and following their progeny in vivo, we showed that postnatal stem cells in different regions produce different types of neurons, even when heterotopically grafted or grown in culture. This suggests that rather than being plastic and homogeneous, neural stem cells are a restricted and diverse population of progenitors. 相似文献
20.
Czupryn A Zhou YD Chen X McNay D Anderson MP Flier JS Macklis JD 《Science (New York, N.Y.)》2011,334(6059):1133-1137
Evolutionarily old and conserved homeostatic systems in the brain, including the hypothalamus, are organized into nuclear structures of heterogeneous and diverse neuron populations. To investigate whether such circuits can be functionally reconstituted by synaptic integration of similarly diverse populations of neurons, we generated physically chimeric hypothalami by microtransplanting small numbers of embryonic enhanced green fluorescent protein-expressing, leptin-responsive hypothalamic cells into hypothalami of postnatal leptin receptor-deficient (db/db) mice that develop morbid obesity. Donor neurons differentiated and integrated as four distinct hypothalamic neuron subtypes, formed functional excitatory and inhibitory synapses, partially restored leptin responsiveness, and ameliorated hyperglycemia and obesity in db/db mice. These experiments serve as a proof of concept that transplanted neurons can functionally reconstitute complex neuronal circuitry in the mammalian brain. 相似文献