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排序方式: 共有251条查询结果,搜索用时 15 毫秒
1.
D Le Guellec L Frappart R Willems 《Biology of the cell / under the auspices of the European Cell Biology Organization》1990,70(3):159-165
We have studied the expression of the fibronectin gene in 7 day-old chick embryo (stage 32) by in situ hybridization at the light and electron microscope levels, using a 397 base-pairs chicken cDNA, labeled by radioisotope or biotin-11dUTP. Cryostat sections of whole chick embryos displayed a selective label on the upper layer of the dermis, fibrous sclera and mesenchymal cells but not on cartilagenous sclera cells. These results show that the expression of the fibronectin gene varies in relation to the morphogenetic events. Hybridization at the ultrastructural level on thin sections of sclera embedded in Lowicryl K4M showed a selective labelling on various cell compartments. Biotin-11dUTP and radiolabeled probes were compared. The labeling was found precisely on the membrane of the rough endoplasmic reticulum and on the nuclear envelope. A few silver grains were located on the nucleus and in the perinucleolar region. This study shows that the postembedding in situ hybridization is a powerful procedure to study the expression of the extracellular protein genes and gives further information on the localization of mRNA. 相似文献
2.
Ultrastructural localization of mRNA encoding for the EGF receptor in human breast cell cancer line BT20 by in situ hybridization 总被引:1,自引:0,他引:1
The EGF receptor (EGF-R), a 170 KD transmembrane glycoprotein, is found at a high level in the BT20 human mammary carcinoma cell line (1 +/- 0.4 x 10(6) sites per cell). In this study, we examined the expression of the EGF-R gene in BT20 cell line by in situ hybridization at the light and electron microscopic level using a human cDNA, corresponding to EGF-R transmembrane and protein kinase domains, labeled with [3H]-, [35S]-, or [32P]-d-ATP. Two treatments were tested to embed cells in Lowicryl resin: the first used fixation and dehydration by progressive lowering of temperature, the second quick freezing and cryosubstitution. The best ultrastructural preservation was obtained with the second procedure without modification of the hybridization signal. EGF-R mRNA was observed principally at the cytoplasmic level, on organelles involved in the protein synthesis process. Labeling was also located on the microvilli which extend into the intercellular space, suggesting that some mRNA would be located in sites where EGF-R is utilized. Some mRNA was observed in the nucleus. This study demonstrates that post-embedding in situ hybridization, after quick freezing and cryosubstitution, is a powerful EM in situ hybridization procedure to study the expression of the EGF-R gene. 相似文献
3.
Jean-Jacques Legrand Cecile Fisch Pierre-Olivier Guillaumat Jean-Marc Pavard Mahmoud Attia Stephane De Jouffrey 《Biomarkers》2013,18(1):63-77
The ovariectomized old cynomolgus monkey is a recognized model of human osteoporosis, and the same species can be used for the assessment of the efficacy and potential toxicity of agents intended to prevent or treat osteoporosis. Several assays have been developed that can measure the same biochemical markers of bone turnover as are used in human patients for the diagnosis and treatment follow-up of bone-related diseases, including osteoporosis. The aim of the present study was to describe the results obtained with these assays in normal control monkeys, their variations with age and sex, and their sensitivity in monitoring the bone turnover induced by ovariectomy in old skeletally mature cynomolgus monkeys. Seven old cynomolgus monkeys were bilaterally ovariectomized and 13 age-matched monkeys were sham-operated. Bone mineral density and biochemical markers were measured before and at regular intervals after surgery for up to 20 months. Total alkaline phosphatase (total ALP), bone-specific alkaline phosphatase isoenzyme (bone ALP) and osteocalcin (OC) were highly correlated to the decrease in bone mineral density (BMD) induced by ovariectomy. Deoxypyridinoline (DPD) measured by enzyme-linked immunoassay was insensitive to the bone resorption induced by ovariectomy, but cross-linked N-telopeptide (NTX-I) was higher in ovariectomized monkeys than in control monkeys. These results demonstrate that reliable biochemical parameters are available to adequately monitor and provide insight into osteoclastic bone resorption and osteoblastic bone formation, the two components of bone turnover in this animal model, and can thus be used to assess the efficacy and toxicity of potential therapeutic agents. 相似文献
4.
Fran?ois Téoulé Cynthia Brisac Isabelle Pelletier Pierre-Olivier Vidalain Sophie Jégouic Carmen Mirabelli Ma?l Bessaud Nicolas Combelas Arnaud Autret Frédéric Tangy Francis Delpeyroux Bruno Blondel 《Journal of virology》2013,87(20):11031-11046
We have shown that the circulating vaccine-derived polioviruses responsible for poliomyelitis outbreaks in Madagascar have recombinant genomes composed of sequences encoding capsid proteins derived from poliovaccine Sabin, mostly type 2 (PVS2), and sequences encoding nonstructural proteins derived from other human enteroviruses. Interestingly, almost all of these recombinant genomes encode a nonstructural 3A protein related to that of field coxsackievirus A17 (CV-A17) strains. Here, we investigated the repercussions of this exchange, by assessing the role of the 3A proteins of PVS2 and CV-A17 and their putative cellular partners in viral replication. We found that the Golgi protein acyl-coenzyme A binding domain-containing 3 (ACBD3), recently identified as an interactor for the 3A proteins of several picornaviruses, interacts with the 3A proteins of PVS2 and CV-A17 at viral RNA replication sites, in human neuroblastoma cells infected with either PVS2 or a PVS2 recombinant encoding a 3A protein from CV-A17 [PVS2-3A(CV-A17)]. The small interfering RNA-mediated downregulation of ACBD3 significantly increased the growth of both viruses, suggesting that ACBD3 slowed viral replication. This was confirmed with replicons. Furthermore, PVS2-3A(CV-A17) was more resistant to the replication-inhibiting effect of ACBD3 than the PVS2 strain, and the amino acid in position 12 of 3A was involved in modulating the sensitivity of viral replication to ACBD3. Overall, our results indicate that exchanges of nonstructural proteins can modify the relationships between enterovirus recombinants and cellular interactors and may thus be one of the factors favoring their emergence. 相似文献
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Bulle Cécile Margni Manuele Patouillard Laure Boulay Anne-Marie Bourgault Guillaume De Bruille Vincent Cao Viêt Hauschild Michael Henderson Andrew Humbert Sebastien Kashef-Haghighi Sormeh Kounina Anna Laurent Alexis Levasseur Annie Liard Gladys Rosenbaum Ralph K. Roy Pierre-Olivier Shaked Shanna Fantke Peter Jolliet Olivier 《The International Journal of Life Cycle Assessment》2019,24(9):1653-1674
The International Journal of Life Cycle Assessment - This paper addresses the need for a globally regionalized method for life cycle impact assessment (LCIA), integrating multiple state-of-the-art... 相似文献
8.
Kotzki PO 《Journal de la Société de Biologie》2004,198(2):163-168
Medical and biological imaging has undergone a revolution in the past decade. Positron emission tomography (PET) has been developed to visualize biochemical and physiological phenomena in living humans and animals. For instance, blood flow, blood volume, glucose metabolism, amino acid metabolism, can be quantitatively estimated by means of PET with various radioactive tracers. This functional and molecular imaging technique has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality. The most widely used radiotracer in routine is 18F-fluorodeoxyglucose (18FDG), which is an analogue of glucose. Since glucose metabolism is increased many fold in malignant tumors, PET has a major role in the field of clinical oncology and recently in cardiology and neurology. PET is also a valuable tool to study cerebral or cardiac binding sites and to image the expression of reporter genes in small animals. In this review, we summarize the most recent developments in PET imaging with particular reference to the radiotracers available and their application. 相似文献
9.
The human maintenance DNA (cytosine-5) methyltransferase (hDNMT1) consists of a large N-terminal regulatory domain fused to a catalytic C-terminal domain by randomly repeated Gly-Lys dipeptides. Several N-terminal deletion mutants of hDNMT1 were made, purified, and tested for substrate specificity. Deletion mutants lacking 121, 501, 540, or 580 amino acids from the N-terminus still functioned as DNA methyltransferases, methylated CG sequences, and preferred hemimethylated to unmethylated DNA, as did the full-length hDNMT1. Methylated DNA stimulated methylation spreading on unmethylated CpG sequences for the full-length and the 121 amino acid deletion hDNMT1 equally well but not for the mutants lacking 501, 540, or 580 amino acids, indicating the presence of an allosteric activation determinant between amino acids 121 and 501. Peptides from the N- and C-termini bound methylated DNA independently. Point mutation analysis within the allosteric region revealed that amino acids 284-287 (KKHR) were involved in methylated DNA-mediated allosteric activation. Allosteric activation was reduced in the double point mutant enzymes D25 (K284A and K285A) and D12 (H286A and R287A). Retinoblastoma gene product (Rb), a negative regulator of DNA methylation, bound to the allosteric site of hDNMT1 and inhibited methylation, suggesting Rb may regulate methylation spreading. 相似文献
10.
Vidalain PO Laine D Zaffran Y Azocar O Servet-Delprat C Wild TF Rabourdin-Combe C Valentin H 《Journal of virology》2002,76(13):6415-6424
In the thymus, epithelial cells comprise a heterogeneous population required for the generation of functional T lymphocytes, suggesting that thymic epithelium disruption by viruses may compromise T-cell lymphopoiesis in this organ. In a previous report, we demonstrated that in vitro, measles virus induced differentiation of cortical thymic epithelial cells as characterized by (i) cell growth arrest, (ii) morphological and phenotypic changes, and (iii) apoptotis as a final step of this process. In the present report, we have analyzed the mechanisms involved. First, measles virus-induced differentiation of thymic epithelial cells is shown to be strictly dependent on beta interferon (IFN-beta) secretion. In addition, transfection with double-stranded RNA, a common intermediate of replication for a broad spectrum of viruses, is reported to similarly mediate thymic epithelial cell differentiation through IFN-beta induction. Finally, we demonstrated that recombinant IFN-alpha, IFN-beta, or IFN-gamma was sufficient to induce differentiation and apoptosis of uninfected thymic epithelial cells. These observations suggested that interferon secretion by either infected cells or activated leukocytes, such as plasmacytoid dendritic cells or lymphocytes, may induce thymic epithelium disruption in a pathological context. Thus, we have identified a new mechanism that may contribute to thymic atrophy and altered T-cell lymphopoiesis associated with many infections. 相似文献