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51.
Bone marrow cells adopt the phenotype of other cells by spontaneous cell fusion   总被引:217,自引:0,他引:217  
Recent studies have demonstrated that transplanted bone marrow cells can turn into unexpected lineages including myocytes, hepatocytes, neurons and many others. A potential problem, however, is that reports discussing such 'transdifferentiation' in vivo tend to conclude donor origin of transdifferentiated cells on the basis of the existence of donor-specific genes such as Y-chromosome markers. Here we demonstrate that mouse bone marrow cells can fuse spontaneously with embryonic stem cells in culture in vitro that contains interleukin-3. Moreover, spontaneously fused bone marrow cells can subsequently adopt the phenotype of the recipient cells, which, without detailed genetic analysis, might be interpreted as 'dedifferentiation' or transdifferentiation.  相似文献   
52.
Summary I125 insulin binding and the uptake of oxygen and 2-deoxyglucose are increased in skeletal muscle after denervation, suggesting an increase in insulin receptors (IR). Sustained increases in the number of affinity of IR molecules may account for some properties of denervated muscle fibres.Supported by the Medical Research Service of the Veterans Administration.  相似文献   
53.
Human genome has ten genes that are collectedly called Ras association domain family (RASSF). RASSF is composed of two subclasses, C-RASSF and N-RASSF. Both N-RASSF and C-RASSF encode Ras association domain-containing proteins and are frequently suppressed by DNA hypermethylation in human cancers. However, C-RASSF and N-RASSF are quite different. Six C-RASSF proteins (RASSF1–6) are characterized by a C-terminal coiled-coil motif named Salvador/RASSF/Hippo domain, while four N-RASSF proteins (RASSF7–10) lack it. C-RASSF proteins interact with mammalian Ste20-like kinases—the core kinases of the tumor suppressor Hippo pathway—and cross-talk with this pathway. Some of them share the same interacting molecules such as MDM2 and exert the tumor suppressor role in similar manners. Nevertheless, each C-RASSF protein has distinct characters. In this review, we summarize our current knowledge of how C-RASSF proteins play tumor suppressor roles and discuss the similarities and differences among C-RASSF proteins.  相似文献   
54.
Riassunto Metionina-S35 è stata incorporata in uova vergini diParacentrotus lividus. In queste l'isotopo si trova per la più gran parte nella frazione solubile in acido tricloracetico al 10%. Attivando le uova partenogeneticamente con acido butirrico si osserva una progressiva perdita di attività di questa frazione ed una rapida incorporazione nei mitocondri. L'andamento del fenomeno è del tutto identico a quello già descritto (Nakano eMonroy) nelle uova normalmente fecondate.

Aided by a Grant from the Rockefeller Foundation.  相似文献   
55.
56.
We report the analysis of a Japanese male using high-throughput sequencing to × 40 coverage. More than 99% of the sequence reads were mapped to the reference human genome. Using a Bayesian decision method, we identified 3,132,608 single nucleotide variations (SNVs). Comparison with six previously reported genomes revealed an excess of singleton nonsense and nonsynonymous SNVs, as well as singleton SNVs in conserved non-coding regions. We also identified 5,319 deletions smaller than 10 kb with high accuracy, in addition to copy number variations and rearrangements. De novo assembly of the unmapped sequence reads generated around 3 Mb of novel sequence, which showed high similarity to non-reference human genomes and the human herpesvirus 4 genome. Our analysis suggests that considerable variation remains undiscovered in the human genome and that whole-genome sequencing is an invaluable tool for obtaining a complete understanding of human genetic variation.  相似文献   
57.
58.
The adenohypophysis (anterior pituitary) is a major centre for systemic hormones. At present, no efficient stem-cell culture for its generation is available, partly because of insufficient knowledge about how the pituitary primordium (Rathke's pouch) is induced in the embryonic head ectoderm. Here we report efficient self-formation of three-dimensional adenohypophysis tissues in an aggregate culture of mouse embryonic stem (ES) cells. ES cells were stimulated to differentiate into non-neural head ectoderm and hypothalamic neuroectoderm in adjacent layers within the aggregate, and treated with hedgehog signalling. Self-organization of Rathke's-pouch-like three-dimensional structures occurred at the interface of these two epithelia, as seen in vivo, and various endocrine cells including corticotrophs and somatotrophs were subsequently produced. The corticotrophs efficiently secreted adrenocorticotropic hormone in response to corticotrophin releasing hormone and, when grafted in vivo, these cells rescued the systemic glucocorticoid level in hypopituitary mice. Thus, functional anterior pituitary tissue self-forms in ES cell culture, recapitulating local tissue interactions.  相似文献   
59.
Generation of F1 hybrid cytotoxic T lymphocytes specific for self H-2   总被引:7,自引:0,他引:7  
K Nakano  I Nakamura  G Cudkowicz 《Nature》1981,289(5798):559-563
Cytotoxic T lymphocytes specific for self H-2 antigens are generated by murine F1 hybrid (H-2 heterozygous) spleen cells cultured with irradiated parental (H-2 homozygous) splenocytes. The effectors bind to heterozygous and homozygous cells bearing the appropriate H-2 alleles but only lyse homozygous targets. Autoreactivity for membrane-bound molecules of normal cells may be a mechanism for regulating cellular interactions.  相似文献   
60.
    
WAVE2, a protein related to Wiskott-Aldrich syndrome protein, is crucial for Rac-induced membrane ruffling, which is important in cell motility. Cell movement is essential for morphogenesis, but it is unclear how cell movement is regulated or related to morphogenesis. Here we show the physiological functions of WAVE2 by disruption of the WAVE2 gene in mice. WAVE2 was expressed predominantly in vascular endothelial cells during embryogenesis. WAVE2-/- embryos showed haemorrhages and died at about embryonic day 10. Deficiency in WAVE2 had no significant effect on vasculogenesis, but it decreased sprouting and branching of endothelial cells from existing vessels during angiogenesis. In WAVE2-/- endothelial cells, cell polarity formed in response to vascular endothelial growth factor, but the formation of lamellipodia at leading edges and capillaries was severely impaired. These findings indicate that WAVE2-regulated actin reorganization might be required for proper cell movement and that a lack of functional WAVE2 impairs angiogenesis in vivo.  相似文献   
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