Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Visna-maedi virus induces in sheep an interstitial lung disease characterised by an accumulation of smooth muscle cells (SMC) or myomatosis. Infection by HIV-1 has been recently associated with disorders of the vessel-derived cells: primary pulmonary hypertension, coronary artery disease and smooth muscle tumors in humans. We hypothesized that, besides their regular targets (i.e. macrophages and lymphocytes), lentiviruses could infect smooth muscle cells. Smooth muscle cell cultures derived from ovine aorta were infected with visna-maedi virus strain K1514. The cultured cells were smooth muscle cells as demonstrated by their antigenic expression of alpha-actin and vimentin. The lentiviral infection of the smooth muscle cells was demonstrated by a typical cytopathic effect (syncytia), the expression of virus specific antigens, and the presence of genomic RNA detected by Northern blot analysis and RT PCR. The detection of a reverse transcriptase activity, the presence of viral RNA in supernatants of infected smooth muscle cells detected by RT PCR and their ability to infect ovine permissive fibroblasts demonstrated a productive infection. The ability of smooth muscle cells to be infected by lentiviruses may participate in the pathogenesis of the tissue damage associated with the lentiviruses such as myomatosis in sheep and vascular disease in humans.
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PMID:Ovine aortic smooth muscle cells allow the replication of visna-maedi virus in vitro. 754 8

Considerable evidence indicates that mRNA associates with structural filaments in the cell (cytoskeleton). This relationship would be an important mechanism to effect mRNA sorting since specific mRNAs could be sequestered at sites within the cell. In addition, it can provide a mechanism for spatial regulation of mRNA expression. However, the precise structural interactions between mRNA and the cytoskeleton have yet to be defined. An objective of this work was to visualize "individual" poly(A) mRNA molecules in situ by electron microscopy to identify their relationship to individual filaments. Poly(A) RNA and filaments were identified simultaneously using antibodies to detect hybridized probe and filaments or actin-binding proteins. In human fibroblasts, most of the poly(A) mRNA (72%) was localized within 5 nm of orthogonal networks of F-actin filaments. Poly(A) mRNA also colocalized with vimentin filaments (29%) and microtubules (< 10%). The sites of mRNA localization were predominantly at filament intersections. The majority of poly(A) mRNA and polysomes colocalized with the actin crosslinking proteins, filamin, and alpha-actinin, and the elongation factor, EF-1 alpha (actin-binding protein; ABP-50). Evidence that intersections contained single mRNA molecules was provided by using a labeled oligo dT probe to prime the synthesis of cDNA in situ using reverse transcriptase. Both the poly(A) and cis sequences of the same mRNA molecule could then be visualized independently. We propose that the cytoskeletal intersection is a mRNA receptor and serves as a "microdomain" where mRNA is attached and functionally expressed.
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PMID:Single mRNAs visualized by ultrastructural in situ hybridization are principally localized at actin filament intersections in fibroblasts. 791 1

Keratinocyte growth factor (KGF) is synthesized and secreted exclusively by mesenchymal cells, and acts through its receptor (KGFR) to stimulate epithelial proliferation. In vivo, KGF and KGFR comprise a mesenchymal-epithelial cell paracrine system that can mediate epithelial cell mitosis. In preliminary work, we noted that KGF was expressed in the rhesus monkey placenta, and we now report on the expression of placental KGF and KGFR mRNAs during the course of gestation in this species. In-situ hybridization revealed that during early gestation, KGF mRNA was strongly expressed in placental mesenchymal cells. These cells, which were also immunoreactive for vimentin, were mainly located on the periphery of the mesenchymal cores of both anchoring and floating villi. KGFR mRNA was expressed in the adjacent trophoblastic epithelium, which was immunoreactive for cytokeratin. In-situ hybridization revealed that KGF mRNA expression was very high in the youngest placentae (34-days gestation) and decreased gradually to minimal levels by late gestation (157 days). Northern blot analysis indicated also that the KGF MRNA signal was strongest in early gestation samples and weakest by late gestation. Analysis for KGFR mRNA by a reverse transcriptase-polymerase chain reaction technique showed that KGFR mRNA expression could be detected at all stages. However, in-situ hybridization indicated that KGFR mRNA expression was highest in early gestation placentae and least in the oldest placentae. Autoradiographs of frozen sections of placenta that had been incubated with [125I]KGF to detect receptor binding showed that grain density over the trophoblast was highest in the youngest and least in the oldest placentae. PCNA and Ki-67 expression followed this same temporal trend. We conclude that the KGF/KGFR system may be important in proliferation of the placental trophoblast during early- to mid-pregnancy in rhesus monkeys.
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PMID:Keratinocyte growth factor and its receptor in the rhesus macaque placenta during the course of gestation. 873 Aug 82

This report describes an intra-abdominal desmoplastic small round-cell tumor in a 29-year-old man that significantly differed from the classically described appearances of this unique tumor. It showed extensive papillary areas, no necrosis, and very little desmoplasia. The latter was limited, paucicellular, and present in areas separate from the papillary structures. Also, areas of back-to-back, single-cell infiltration, which mimicked lobular breast carcinoma, were present. These epithelial features suggested the diagnosis of adenocarcinoma or peculiar mesothelioma. But, the immunohistochemical features (tumor cells positive for keratin, desmin, and vimentin) were more consistent with an intra-abdominal desmoplastic small round-cell tumor. The diagnosis became clear after application of reverse transcriptase-polymerase chain reaction techniques to formalin-fixed, paraffin-embedded tissue, which showed the presence of a 100-base pair product containing the fusion junction of Ewing's sarcoma-1 exon 7 to Wilms' tumor-1 exon 8. This feature is considered unique to intra-abdominal desmoplastic small round-cell tumors. This case illustrates the less common histologic findings that can be found in intra-abdominal desmoplastic small round-cell tumor. This deviation from the classic histologic findings may be an expression of an uncommon morphologic variant and/or partially produced by the effects of prior chemotherapy. In either event, only by illustrating the various histologic appearances of intra-abdominal desmoplastic small round-cell tumor are the chances increased for the accurate diagnosis of this aggressive neoplasm with a poor prognosis.
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PMID:Intra-abdominal desmoplastic small round-cell tumor: expansion of the pathologic profile. 878 11

The presence of t(11;22)(q24;q12) is often considered diagnostic of Ewing sarcoma and peripheral primitive neuroectodermal tumor (pPNET). We report a case of a polyphenotypic tumor that possessed this translocation as detected by reverse transcriptase polymerase chain reaction (RT-PCR). This tumor was positive for vimentin, desmin, low-molecular-weight keratin, neuron-specific enolase, S-100 protein, and CD57 by immunohistochemistry. Of note, the tumor was negative for MIC2. The tumor had double-minute chromosomes with > 100 copies of the MDM2 gene. Thus, the presence of the t(11;22)(q24;q12) translocation should not be considered diagnostic of Ewing sarcoma and pPNET in the absence of supporting histologic evidence such as positive staining for MIC2. The presence of this translocation in Ewing sarcoma and pPNET has been taken as evidence that these two tumors are related. Rather than extending this relationship to include some polyphenotypic tumors, other tumors may acquire this genetic change during tumor progression. Treatment regimens for tumors may be better based on phenotype rather than genotype when these two profiles are seemingly in conflict.
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PMID:Intra-abdominal polyphenotypic tumor. 896 28

Human brown pre-adipocytes were immortalized by microinjection of the genes encoding simian virus 40 T and t antigens under the control of the human vimentin promotor. The transfected pre-adipocytes were cultured for several months with no loss of their morphological characteristics. These cells accumulate lipids and differentiate into adipocytes when treated with insulin, triiodothyronine and dexamethazone. The mRNA of various adipocyte markers was detected by reverse transcriptase-polymerase chain reaction analysis, including hormone-sensitive lipase, lipoprotein lipase, adipsin, glucose transporters 1 and 4, the uncoupling protein (specific of brown adipocytes), and leptin, the product of the ob gene. Pharmacological analyses indicated that the beta3-adrenoceptor is the predominant beta-adrenoceptor subtype in PAZ6 cells and that this receptor subtype is functionally coupled to adenylate cyclase and lipolysis. The immortalization of human adipocytes will permit pharmacological analysis of the human beta3-adrenoceptor function in adipose cells and will allow detailed studies of human adipocyte differentiation.
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PMID:Human immortalized brown adipocytes express functional beta3-adrenoceptor coupled to lipolysis. 913 67

Variants of the human ovarian carcinoma cell line, OAW42, exhibiting low-level intrinsic resistance (OAW42-SR) and drug-induced higher-level resistance (OAW42-A1 & OAW42-A), were studied along with a sensitive clonal population (OAW42-S) which was isolated from OAW42-SR. Expression of the MDR-associated protein P-170, the more recently discovered LRP (lung resistance-related protein) and MRP (multidrug resistance-associated protein), topoisomerase II alpha and beta, GST pi and the cytoskeletal proteins, cytokeratin 8 and vimentin, were studied (using immunocytochemistry and Western blotting techniques) in conjunction with drug (doxorubicin) accumulation and subcellular distribution. Expression of mRNA for P-170, MRP, topoisomerase 11 alpha and beta and GST pi was studied using RT-PCR (reverse transcriptase polymerase chain reaction). Results indicate differential co-expression of four MDR-associated parameters (P-170, MRP, LRP and reduced topoisomerase II alpha and beta) in the OAW42-SR and OAW42-A1 variants, whereas resistance in the OAW42-A variant appeared to be mainly P-170 mediated. Comparable amounts of MRP and greater amounts of LRP were detected in the OAW42-S cells compared to the OAW42-SR variant (which showed increased resistance compared to the OAW42-S cells), but all cell lines expressed similar low-level amounts of MRP mRNA (by RT-PCR). GST pi levels did not differ markedly between variants. Increased levels of the cytoskeletal proteins were observed with increasing levels of resistance. The relative resistance of the variants, OAW42-SR and OAW42-A1, compared with OAW42-S was seen to change during increased serial passaging of the cells. There was greater drug accumulation by the sensitive OAW42-S cell line compared with that of the resistant variants, particularly the most highly resistant OAW42-A cells. Both verapamil and cyclosporin A effectively restored the accumulation defects seen in the resistant variants, cyclosporin A being the more effective of the two. Sub-cellular location of drug was predominantly in the nucleus with maximum levels seen in the sensitive OAW42-S variant and minimum levels in the most resistant OAW42-A clone.
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PMID:Co-expression of MDR-associated markers, including P-170, MRP and LRP and cytoskeletal proteins, in three resistant variants of the human ovarian carcinoma cell line, OAW42. 927 50

Using both tumor specimen and cultured tumor cells, we have studied the differentiation of a pineocytoma by light and electron microscopy (EM) and immunohistochemical demonstration of glial, neuronal and neuroendocrine markers. Only interstitial cells were labeled with anti-glial fibrillary acidic protein and anti-S100 protein antibodies. Synaptophysin, neurofilaments and tau labeling was found in cells forming the pineocytomatous rosettes. Some cells also bound the anti-tryptophan hydroxylase antibody (TPOH), but no staining was seen after application of anti-chromogranin A or S-antigen antibodies. EM provided evidence for neurosensory differentiation demonstrating the presence of vesicle-crowned rodlets, cilia (9+0) and fibrous filaments. In culture, tumor cells proliferated slowly and showed positive immunolabeling for vimentin and TPOH. Expression of mRNA coding for TPOH, serotonin N-acetyltransferase, hydroxyindole-O-methyl-transferase and c-myc was found in the tumor using reverse transcriptase-polymerase chain reaction. These results demonstrate neuronal differentiation of this pineocytoma and suggest that the neoplastic pineal cells are capable of synthesizing serotonin and melatonin.
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PMID:Immunohistochemical, ultrastructural, biochemical and in vitro studies of a pineocytoma. 960 Jun

MFE-280 endometrial cancer cells express PP14 (placental protein 14) in vitro. PP14 is normally found in the secretory endometrium and in placental tissue. MFE-280 cells, which are tumorigenic in nude mice, were derived from a recurrent, poorly differentiated endometrial carcinoma. The cells were initially grown in suspension culture and later transferred to monolayer cultures. Karyotyping revealed near-diploidy with a complex heterogeneous aberration pattern. MFE-280 cells were positive for the cytokeratins 7, 8, 18 and 19 as well as for vimentin. The expression of PP14 in MFE-280 cells was demonstrated by immunochemistry and reverse transcriptase--polymerase chain reaction. PP14-mRNA was also detected in one out of five endometrial cancer specimen. In tumor tissue the expression of PP14 was not dependent on progestins.
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PMID:Expression of placental protein 14 by the new endometrial cancer cell line MFE-280 in vitro and by endometrial carcinomas in vivo. 961 81

Cells with fibroblast-like features were isolated from the villous tissue of normal term human placentas. Immunocytochemical characterization of the cells showed that they were vimentin-positive but negative for factor-VIII, CD14 and CD4. Thus, the cells are mesenchymal and are not endothelial cells, macrophages or trophoblast. These cells were exposed to nine different cell-free virus isolates, including seven isolates of human immunodeficiency virus type 1 (HIV-1), one HIV-2 isolate and one simian immunodeficiency virus isolate (SIVmac251). The susceptibility of the cells to infection was evaluated by immunocytochemical and virological techniques. No evidence of infection could be found using immunofluorescence microscopy or by p24 antigen capture and reverse transcriptase assays. However, virus rescue experiments using 11 different target cell types provided evidence that the placental fibroblasts were susceptible to infection with HIV-1Lai, HIV-1IIIB, HIV-2CBL-20, and SIVmac251, yet were resistant to infection by all other isolates. The infected fibroblasts exhibited neither cytopathic effects nor released virus into the culture medium. For each infected fibroblast population, some, but not all, indicator target cell lines or human peripheral blood mononuclear cells were able to rescue the respective virus. Based on these observations, we conclude that placental fibroblasts can be infected with HIV during transplacental transmission and could act as virus reservoirs, capable of infecting other fetal cells.
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PMID:Infection of primary human placental fibroblasts with HIV-1, HIV-2, and SIV. 967 89


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