共查询到20条相似文献,搜索用时 31 毫秒
1.
R Y Chuang L F Chuang R T Kawahata M Israel 《The Journal of biological chemistry》1983,258(2):1062-1065
The effects of N-trifluoroacetyladriamycin-14-valerate on the uptake of [3H]thymidine and its incorporation into DNA of human P3HR-1 lymphoma cells were studied. In the absence of the drug, at 0 degrees C, [3H]thymidine was transported into the cells but not incorporated into DNA, as determined by both the trichloroacetic acid-soluble and -precipitable counts obtained with the cells. At 37 degrees C, [3H]thymidine was readily transported into the cells and incorporated into DNA. In the presence of the drug, both [3H]thymidine uptake (as shown by acid-soluble counts) and the amount of its incorporation into acid-precipitable materials were markedly reduced. However, the uptake of [3H]thymidine at 0 degrees C was found to be equally sensitive to drug inhibition as at 37 degrees C. The incorporation at 37 degrees C of [3H]thymidine into acid-precipitable materials of the cells, which had been prelabeled at 0 degrees C with [3H]thymidine, was found to be insensitive to inhibition by the drug. The in vitro activities of DNA polymerases alpha and beta purified from human P3HR-1 cells were also found not to be susceptible to inhibition. Nuclei purified from cells pretreated with the drug continued to synthesize DNA. The cytofluorograms of the cells treated with the drug indicated that the treated cells accumulated at the G2/M phase, whereas the S phase of the cells was not arrested. These results suggest that N-trifluoroacetyladriamycin-14-valerate inhibits [3H]thymidine uptake but not cellular DNA synthesis in human P3HR-1 lymphoma cells. 相似文献
2.
Fukamachi H 《Development, growth & differentiation》2006,48(1):1-13
3.
Dibutyryl cyclic AMP treatment of 3T3 and SV40 virus-transformed 3T3 cells in aggregates. Effects on mobility and cell contact ultrastructure
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The random cell movement of BALB/c 3T3 and SV40 virus-transformed BALB/c 3T3 cells within homogeneous aggregates was studied by observing the degree of penetration of newly attached [3H]thymidine-labeled cells into the interior of the aggregates. The 3T3 cells penetrated into 3T3 aggregates an average of 0.89 cell diameter in 1.5 days, whereas the SV40-3T3 cells penetrated into SV40-3T3 aggregates an average of 3.20 cell diameters in the same time. Treatment of the aggregates with theophylline, theophylline plus prostaglandin E1, or theophylline plus dibutyryl cyclic AMP all decreased the penetration of the SV40-3T3 cells into SV40-3T3 aggregates (2.36, 1.22, and 0.79 cell diameters, respectively). The same treatments had little effect on 3T3 aggregates. The ultrastructure of 3T3 and SV40-3T3 cells in aggregates was examined by transmission electron microscopy. The 3T3 cells in aggregates were surrounded by microvilli and lamellipodia which were in contact with neighboring cells, whereas SV40-3T3 cells were nearly devoid of microvilli and lamellipodia and made contact at broader, less regular surface undulations. Treatment with theophylline plus dibutyryl cyclic AMP resulted in the appearance of microvilli on SV40-3T3 cells and also appeared to increase the area of intercellular contacts in both 3T3 and SV40-3T3 cells. These observations were supported for the surface cells of the aggregates by scanning electron microscopy. 相似文献
4.
Zangani D Darcy KM Masso-Welch PA Bellamy ES Desole MS Ip MM 《Differentiation; research in biological diversity》1999,64(2):91-101
It has previously been shown that mammary stromal cells possess the ability to maintain a fibroblast-like phenotype or differentiate in vitro into mature adipocytes in a hormone-dependent manner. This paper reports that rat mammary stromal cells can also differentiate into capillary-like structures in vitro when cultured on a reconstituted basement membrane (RBM). The differentiation potential of mammary stromal cells was compared with that of human umbilical vein endothelial cells (HUVEC) and 3T3-L1 preadipocytes. When cultured on plastic, mammary stromal cells, 3T3-L1 and HUVEC maintained a fibroblast-like phenotype. Mammary stromal cells and 3T3-L1, but not HUVEC, differentiated into mature adipocytes when cultured in adipogenic medium. When plated on reconstituted basement membrane, all three cell types began to migrate and organize themselves into an interconnected capillary network. By 18-20 h, mammary stromal cells organized into complex, highly branched capillary-like tubules whereas 3T3-L1 cells and HUVEC formed more simple structures. Cross-sectional analysis demonstrated the presence of an internal lumen. Mammary stromal cells were unique in their ability to progressively develop into a three-dimensional, highly branched network invading the RBM surface. The network formation was enhanced by the presence of vascular endothelial growth factor (VEGF) and was inhibited by the anti-angiogenic drug suramin. Western blotting analysis demonstrated the presence of the endothelial-specific marker flk-1, as well as the presence of the tight-junction-associated protein ZO-1. Mammary stromal cell differentiation into capillary structures was not a terminal state, since these cells were still able to differentiate into adipocytes when exposed to adipogenic medium. These findings suggest that mammary stromal cells differentiate into fibroblasts, adipocytes or vascular structures in a hormone- and substatum-dependent manner, and may explain the dramatic changes in stromal composition during both normal mammary gland development and tumorigenesis. 相似文献
5.
Margaret M. Jastreboff Etsuro Ito Joseph R. Bertino Ramaswamy Narayanan 《Experimental cell research》1987,171(2):513-517
Electroporation was used to introduce high-molecular-weight DNA into murine hematopoietic cells and NIH3T3 cells. CCRF-CEM cells were stably transfected with SV2NEO plasmid and the genomic DNA from G-418-resistant clones (greater than 65 kb) was introduced into mouse bone marrow and NIH3T3 cells by electroporation. NEO sequences and expression were detected in the hematopoietic tissues of lethally irradiated mice, with 24% of individual spleen colonies expressing NEO. The frequency of genomic DNA transfer into NIH3T3 cells was 0.25 X 10(-3). Electroporation thus offers a powerful mode of gene transfer not only of cloned genes but also of high-molecular-weight DNA into cells. 相似文献
6.
In order to assess whether experimental allergic encephalomyelitis (EAE), a putative animal model for multiple sclerosis (MS), is an ongoing chronic disorder, we have studied the permeability of spinal cords of Lewis rats with EAE to 3H-uridine- or 3H-thymidine-labeled lymphoid cells obtained from thymuses of naive donors or from draining lymph nodes of donors injected with guinea pig spinal cord + complete Fruend's adjuvant (CFA), guinea pig myelin basic protein + CFA, or with CFA alone. During the acute clinical phase of EAE there is a high-level infiltration of 3H-thymidine- or 3H-uridine-labeled cells into the spinal cords. After clinical recovery from EAE up to 58 days post-inoculation, there is a low-level infiltration of 3H-thymidine-labeled cells into the spinal cords. A similar infiltration into the spinal cords by 3H-uridine-labeled cells was not detected. Donor cells from animals immunized with CFA alone showed similar levels of infiltration into the spinal cords of animals with EAE as donor cells from animals immunized with the encephalitogenic emulsion. Spinal cords from recipients immunized with CFA alone showed no increased permeability to labeled cells. Heat-killed labeled cells did not migrate into the spinal cords of animals with EAE. We conclude that a) EAE is a chronic disease and in this regard is a valid model for MS; and B) in the chronic phase of EAE, recently divided cells (3H-thymidine-labeled cells) show higher levels of migration into the target tissue than 3H-uridine-labeled cells. 相似文献
7.
Tomohiro Yamauchi Yasumasa Kuroda Takahiro Morita Hideo Shichinohe Kiyohiro Houkin Mari Dezawa Satoshi Kuroda 《PloS one》2015,10(3)
Objective
Bone marrow stromal cells (BMSCs) are heterogeneous and their therapeutic effect is pleiotropic. Multilineage-differentiating stress enduring (Muse) cells are recently identified to comprise several percentages of BMSCs, being able to differentiate into triploblastic lineages including neuronal cells and act as tissue repair cells. This study was aimed to clarify how Muse and non-Muse cells in BMSCs contribute to functional recovery after ischemic stroke.Methods
Human BMSCs were separated into stage specific embryonic antigen-3-positive Muse cells and -negative non-Muse cells. Immunodeficient mice were subjected to permanent middle cerebral artery occlusion and received transplantation of vehicle, Muse, non-Muse or BMSCs (2.5×104 cells) into the ipsilateral striatum 7 days later.Results
Motor function recovery in BMSC and non-Muse groups became apparent at 21 days after transplantation, but reached the plateau thereafter. In Muse group, functional recovery was not observed for up to 28 days post-transplantation, but became apparent at 35 days post-transplantation. On immunohistochemistry, only Muse cells were integrated into peri-infarct cortex and differentiate into Tuj-1- and NeuN-expressing cells, while negligible number of BMSCs and non-Muse cells remained in the peri-infarct area at 42 days post-transplantation.Conclusions
These findings strongly suggest that Muse cells and non-Muse cells may contribute differently to tissue regeneration and functional recovery. Muse cells may be more responsible for replacement of the lost neurons through their integration into the peri-infarct cortex and spontaneous differentiation into neuronal marker-positive cells. Non-Muse cells do not remain in the host brain and may exhibit trophic effects rather than cell replacement. 相似文献8.
Yan-Wu G Yi-Quan K Ming L Ying-Qian C Xiao-Dan J Shi-Zhong Z Wang-Ming Z Chuan-Zhi D 《Neurochemical research》2011,36(5):783-792
Mesenchymal stem cells are capable of differentiating into Schwann-like cells. In this study, we induced human umbilical-cord
mesenchymal stem cells (HUMSCs) in vitro into neurospheres constituted by neural stem-like cells, and further into cells bearing
strong morphological, phenotypic and functional resemblances with Schwann-like cells. These HUMSC-derived Schwann-like cells,
after grafting into the injured area of the rats’ spinal cord injury (SCI), showed a partial therapeutic effect in terms of
improving the motor function. Neurotrophin-3 (NT-3) was reported to improve the local microenvironment of the grafted cells,
and we, therefore, further tested the effect of Schwann-like cell grafting combined with NT-3 administration at the site of
cell transplantation. The results showed that NT-3 administration significantly promoted the survival of the grafted cells
in the host-injured area. Significant improvement in rats treated by Schwann-like cell grafting combined with NT-3 administration
was demonstrated in the behavioral test as compared with that in animal models received the cell grafting only. These results
suggest that transplantation of the Schwann-like cells combined with NT-3 administration may represent a new strategy of stem
cell therapy for spinal cord injury. 相似文献
9.
The effects of estrogen on the uridine uptake into cells were examined in primary cultures of liver parenchymal cells from Xenopus laevis. The total uptake of [3H]uridine into the estrogen-treated cells and its incorporation into RNA were about 1.5 times higher than the values for control cells. The uptake of [3H]adenosine and its incorporation into RNA were not affected by estrogen. An experiment in which liver parenchymal cells were double labeled with [3H]uridine and [3H]adenosine showed that estrogen elevated the specific radioactivity of the UTP pool 1.4-fold the value found for the control cells, but that of the ATP pool was not altered by estrogen. Short term labeling revealed that estrogen did not significantly alter the rate of the initial uptake of [3H]uridine into the cells, but it did stimulate [3H]uridine phosphorylation about 1.7-fold. Uridine kinase activity measured in cell-free extracts of hepatocytes treated with estrogen had a value 1.6 times that of the control cells. These data indicate that the stimulation of [3H]uridine uptake and phosphorylation in Xenopus laevis hepatocytes in the presence of estrogen is caused by the enhancement of uridine kinase activity. 相似文献
10.
Disruption of alpha beta but not of gamma delta T cell development by overexpression of the helix-loop-helix protein Id3 in committed T cell progenitors.
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B Blom M H Heemskerk M C Verschuren J J van Dongen A P Stegmann A Q Bakker F Couwenberg P C Res H Spits 《The EMBO journal》1999,18(10):2793-2802
11.
Experiments on the introduction of the regulatory subunit of cAMP-dependent protein kinase type II (RII) into NIH 3T3 cells clearly demonstrated its translocation into the nucleus. The labelled protein was incorporated into erythrocyte ghosts and their fusion with the cells was carried out. The dynamics of distribution of the labelled RII in NIH 3T3 cells was studied by the method of historadiography. It was found that during the next few hours after its penetration into the cytoplasm, the protein translocates into the nucleus and concentrates in the immediate proximity to the nucleoli. 相似文献
12.
Inositol incorporation into phosphoinositides in retinal horizontal cells of Xenopus laevis: enhancement by acetylcholine, inhibition by glycine 总被引:1,自引:0,他引:1
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The absorption of light by photoreceptor cells leads to an increased incorporation of [2-3H]inositol into phosphoinositides of horizontal cells in the retina of Xenopus laevis in vitro. We have identified several retinal neurotransmitters that are involved in regulating this response. Incubation with glycine, the neurotransmitter of an interplexiform cell that has direct synaptic input onto horizontal cells, abolishes the light effect. This inhibition is reversed by preincubation with strychnine. Acetylcholine added to the culture medium enhances the incorporation of [2-3H]inositol into phosphoinositides in horizontal cells when retinas are incubated in the dark. This effect is inhibited by preincubation with atropine. However, atropine alone does not inhibit the light-enhanced incorporation of [2-3H]inositol into phosphoinositides in the retina. gamma-Aminobutyric acid, the neurotransmitter of retinal horizontal cells in X. laevis, as well as dopamine and norepinephrine, have no effect on the incorporation of [2-3H]inositol into phosphoinositides. These studies demonstrate that the light-enhanced incorporation of [2-3H]inositol into phosphoinositides of retinal horizontal cells is regulated by specific neurotransmitters, and that there are probably several synaptic inputs into horizontal cells which control this process. 相似文献
13.
Objective
To study usefulness of bone marrow progenitor cells (BPCs) epigenetically altered by chromatin modifying agents in mediating heart repair after myocardial infarction in mice.Methods and Results
We tested the therapeutic efficacy of bone marrow progenitor cells treated with the clinically-used chromatin modifying agents Trichostatin A (TSA, histone deacetylase inhibitor) and 5Aza-2-deoxycytidine (Aza, DNA methylation inhibitor) in a mouse model of acute myocardial infarction (AMI). Treatment of BPCs with Aza and TSA induced expression of pluripotent genes Oct4, Nanog, Sox2, and thereafter culturing these cells in defined cardiac myocyte-conditioned medium resulted in their differentiation into cardiomyocyte progenitors and subsequently into cardiac myocytes. Their transition was deduced by expression of repertoire of markers: Nkx2.5, GATA4, cardiotroponin T, cardiotroponin I, α-sarcomeric actinin, Mef2c and MHC-α. We observed that the modified BPCs had greater AceH3K9 expression and reduced histone deacetylase1 (HDAC1) and lysine-specific demethylase1 (LSD1) expression compared to untreated BPCs, characteristic of epigenetic changes. Intra-myocardial injection of modified BPCs after AMI in mice significantly improved left ventricular function. These changes were ascribed to differentiation of the injected cells into cardiomyocytes and endothelial cells.Conclusion
Treatment of BPCs with Aza and TSA converts BPCs into multipotent cells, which can then be differentiated into myocyte progenitors. Transplantation of these modified progenitor cells into infarcted mouse hearts improved left ventricular function secondary to differentiation of cells in the niche into myocytes and endothelial cells. 相似文献14.
Atsuko Inoue Akira Nagafuchi 《Biochemical and biophysical research communications》2009,390(3):564-569
Retinoic acid (RA) induces F9 cells, the mouse teratocarcinoma cells, to differentiate into primitive endoderm and further into visceral and parietal endoderm depending on the culture conditions. To elucidate the instructive mechanisms involved in the differentiation steps we investigated the effects of Wnt-signaling members, Wnt3a and β-catenin, on the differentiation of F9 cells and β-catenin-deficient F9 cells (βT cells). RA up-regulated the expression of differentiation markers for primitive, visceral and parietal endoderm in F9 cells but not for visceral endoderm in βT cells. Wnt3a or leukemia inhibitory factor (LIF) inhibited the RA-induced differentiation in F9 cells. LIF but not Wnt3a could inhibit differentiation in βT cells. RA evoked ZO-1α+ signals at cell-to-cell contacts in F9 cells in a Wnt3a sensitive manner. The results suggest that Wnt3a inhibits differentiation into endoderm through a pathway involving β-catenin, and β-catenin might be necessary in the process leading from primitive to visceral endoderm in F9 cells. 相似文献
15.
K Hayasaka M Sato H Mitani A Shima 《Comparative biochemistry and physiology. B, Comparative biochemistry》1990,96(2):349-354
1. Plasmids bearing the G418-resistant gene neo were transfected into cultured fish cells RBCF-1 by electroporation at an efficiency comparable to that in NIH3T3 cells. 2. Transfection of plasmids bearing both neo and activated human c-Ha-ras into NIH3T3 and RBCF-1 cells resulted in the malignant transformation of the former but not of the latter cells. 相似文献
16.
Movement of plasma-membrane sterols to the endoplasmic reticulum in cultured cells. 总被引:2,自引:0,他引:2
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The spontaneous turnover of plasma-membrane sterols, as measured by their transfer to the endoplasmic reticulum, was measured in quiescent cultured human skin fibroblasts and monkey arterial smooth-muscle cells. The plasma-membrane sterol pool was pulse-labelled with trace amounts of either [3H]desmosterol or [3H]cholesterol. We then measured the enzymic conversion of [3H]desmosterol into [3H]cholesterol and of [3H]cholesterol into [3H]cholesteryl esters in intact cells. Depending on the probe used, markedly different transfer or conversion rates were found in these cells. In quiescent human skin fibroblasts, incubated in a serum-free medium, about 1.1% of the plasma-membrane [3H]desmosterol was converted into [3H]cholesterol/h, whereas in monkey arterial smooth-muscle cells the corresponding rate was 0.4%. Under similar experimental conditions, these cells esterified less than 0.02% (fibroblasts) and 0.12% (smooth-muscle cells) of the plasma-membrane [3H]cholesterol/h. The movement of sterols from the plasma membrane to the endoplasmic reticulum, as measured by the conversion of [3H]desmosterol into [3H]cholesterol was not blocked by colchicine, but was markedly enhanced by 3% (w/v) dimethyl sulphoxide. In all, these results indicate that plasma-membrane sterols of cultured cells are continuously transferred to the interior of the cell at a rate substantially higher than previously appreciated. This turnover of plasma-membrane sterol molecules took place even when there was no mass transfer of sterols into the cells. 相似文献
17.
18.
Kobayashi M Takaori-Kondo A Shindo K Abudu A Fukunaga K Uchiyama T 《Journal of virology》2004,78(15):8238-8244
Human APOBEC3G (huAPOBEC3G), also known as CEM15, is a broad antiretroviral host factor that deaminates dC to dU in the minus strand DNA of human immunodeficiency virus type 1 (HIV-1), other lentiviruses, and murine leukemia virus (MLV), thereby creating G-to-A hypermutation in the plus strand DNA to inhibit the infectivity of these viruses. In this study, we examined the antiretroviral function of a murine homologue of APOBEC3G (muAPOBEC3G) on several retrovirus systems with different producer cells. MuAPOBEC3G did not suppress the infectivity of murine retroviral vectors produced from human or murine cells, whereas it showed antiviral activity on both wild-type and Deltavif virions of HIV-1 in human cells. In contrast, huAPOBEC3G showed broad antiviral activity on HIV-1 and murine retroviral vectors produced from human cells as well as murine cells. These data suggested that muAPOBEC3G does not possess antiretroviral activity on murine retroviruses and has a different target specificity from that of huAPOBEC3G and that huAPOBEC3G works as a broad antiviral factor not only in human cells but also in murine cells. A functional interaction study between human and murine APOBEC3G supported the former hypothesis. Furthermore, studies on the expression of APOBEC3G in producer cells and its incorporation into virions revealed that muAPOBEC3G is incorporated into HIV-1 virions but not into MLV virions. Thus, muAPOBEC3G cannot suppress the infectivity of murine retrovirus because it is not incorporated into virions. We suggest that murine retroviruses can replicate in murine target cells expressing muAPOBEC3G because they are not targets for this enzyme. 相似文献
19.
20.
大鼠催乳素基因真核细胞可表达性质粒的构建及应用研究 总被引:4,自引:0,他引:4
735bp的PRLcDNA片段从质粒PRL-SP65#1中回收后,用粘性末端连接法将其重组到真核表达载体pcDNA3上,筛选出正向连接重组体pcDNA3-PRLS和反向连接重组体pcDNA3-PRLAS。将重组体pcDNA3-PRLs和空载体pcDNA3分别转入NIH3T3细胞系,用G418筛选出阳性细胞后与未转染的NIH3T3细胞在加E2和不加E2的情况下,用原位杂交的方法,分别用PRLcDNA探针和原癌基因c-H-rascDNA探针进行检测,未转染的NIH3T3细胞在加E2和不加E2时都几乎无催乳素基因的表达,同样,转入空载体的NIH3T3细胞也无PRL的表达,而转入重组体pcDNA3-PRLS的NIH3T3细胞则有大量的PRL基因的表达,与对照组相比有显著差异(P<0.01)。正常和转入空载体的NIH3T3细胞有一定程度的原癌基因c-H-ras的表达,当分别加入E2和转入重组体pcDNA3-PRLS后,NIH3T3细胞中的c-H-ras基因表达水平都显著升高(P<0.05)。 相似文献