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)

Morphologic, tissue culture, immunologic, and biochemical methods have been used in an attempt to detect and characterize oncogenic viruses or their subviral components in cells derived from human prostatic carcinoma (PrCa) or benign prostatic hyperplasia (BPH). Electron microscopy was used to characterize the ultrastructural features of normal and neoplastic prostatic tissue. Examination of specimens of prostatic tissue from 34 patients with PrCa, ten patients with BPH, and three patients with bladder tumor (BT) revealed the presence of particles resembling type-C virus in three cases of PrCa and structures resembling budding type-C virus particles in one case of BPH. Fifty human prostatic tissue specimens have been set in tissue culture, of which 30 have been successfully grown for varying periods of time. Of 20 currently active cultures, nine consist primarily of epithelial cells. Immunofluorescence and mixed hemadsorption tests of cells derived from benign and malignant prostatic tissue and sera derived from patients with PrCa, BPH, BT, and other types of tumors, and from normal donors revealed that sera from patients with PrCa, BPH, or BT contain antibodies to antigens in cells derived from PrCa, BPH, or BT. The nature of these antigen-antibody reactions is under study. Initial biochemical studies have not detected reverse transcriptase in the tissue culture fluid from a small number of sparsely growing PrCa cultures nor specific gene sequences homologous to murine leukemia virus-Rauscher genomic RNA in preparations of either normal or malignant prostatic cell DNA. The results of these preliminary studies have demonstrated the applicability of the techniques employed to the study of the relationship of viruses to human PrCa and have provided a number of promising leads for further investigation.
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PMID:Virologic and immunologic studies of human prostatic carcinoma. 4 14

SV-40-transformed hamster prostatic tissue has been previously evaluated as a model for human prostatic carcinoma. Because the original cell line was lost, Syrian golden hamster prostatic tissue has been established in explant culture and infected with a 10-6-cell tissue culture infectious dose (50 percent effective) of SV40. After in vitro transformation, the cells were produced in quantity and 60 times 10-6 cells were injected into adult male Syrian golden hamsters 24 hours after 400 rads of whole-body radiation. After 60-90 days, a small palpable tumor developed. These tumors could be serially transplanted in adult male animals without immunosuppression. The tumor cells were established in tissue culture and the cells were returned to adult animals without immunosuppression where they rapidly produced fast-growing tumors. The solid tumors were composed of sheets of pleomorphic polygonal cells with large nuclei and many nucleoli; they resembled undifferentiated human prostatic carcinoma. In vitro, the cultures contained small, rapidly growing cells with a population doubling time of about 1.3 days. The cells carried the SV 40-specific antigen. The modal chromosome number was 66-68 with a distribution of 47-120. Cells exposed to 2-bromo-5'-deoxyuridine in culture did not release particles with RNA-dependent DNA polymerase activity. Endocrine sensitivity in vivo and in vitro is undertermined to date.
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PMID:Properties of prostatic cultures transformed by SV40. 4 16

A fibroblast-like cell culture was established from a stomach biopsy of a patient with metastatic adenocarcinoma. One of the cultures, at the 6th passage level, left unattended for a month at 37 degrees, produced numerous foci of epithelioid cells. Upon subculturing, an epithelioid cell line, designated HCCL (human carcinoma cell line), was established. The HCCL cells released particles possessing the characteristics of oncornaviruses: density 1.175 g/ml, cores with a density of 1.22-1.26 g/ml, high-molecular-weight RNA (60-70S) and RNA-instructed DNA polymerase activity (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Inoculation of particles released from HCCL cells into cultures of human embryo muscle fibroblasts resulted in the appearance of foci of transformed cells.
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PMID:Transformation of cultured human embryonic fibroblasts by oncornavirus-like particles released from a human carcinoma cell line. 5 57

A foamy virus present in human nasopharyngeal carcinoma tissue was studied for a number of biological properties, including range of cellular susceptibility, growth curve, evolution of cytopathic effect in relation to cellular fusion and intracellular viral distribution, reverse transcriptase activity, and buoyant density. The virus was also studied immunologically and found to be closely related to the chimpanzee foamy viruses, particularly simian foamy virus type 6, with which it shares common antigens in complement-fixing, fluorescent, and neutralizing antibody tests. In view of this close immunological relationship and the failure to find antibody to the human isolate in sera from more than 250 humans, including 50 patients with nasopharyngeal carcinoma and Burkitt's lymphoma, it is suggested that the isolate is not a human representative of the foamy virus group but rather a variant strain of chimpanzee foamy virus.
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PMID:Human foamy virus: further characterization, seroepidemiology, and relationship to chimpanzee foamy viruses. 20 31

A new method of simultaneous analysis of the relative abundance of the most abundant individual mRNA's in poly(A)(+)-RNA preparations is described. The method is based on the synthesis of short (10-20 nucleotides) cDNA products by reverse transcription of poly(A)(+)-RNA primed with 5'-labeled oligonucleotides of 9 nucleotide lengths. Three natural nucleotides and one terminator nucleotide are used as substrates for reverse transcriptase. The numbers, lengths and sequence of the oligonucleotides used as primers were chosen to provide more than a 90% probability that synthesis would be initiated from any individual RNA present in the poly(A)(+)-RNA, thus assuring comprehensive analysis of RNA with abundance higher than 0.01%. Each primer produces about 20-60 bands per track following polyacrylamide electrophoresis under denaturing conditions. A full set of 30 oligonucleotides used to analyze a poly(A)(+)-RNA preparation produces an electrophoretic pattern with information capacity similar to that obtained from high resolution 2-dimensional electrophoresis of protein. Using this method we show that the patterns of poly(A)(+)-RNA differ from tissue to tissue, from normal tissues to neoplastic tissue (human myoma of uterus) and during differentiation of a F9 embryonic carcinoma cell line.
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PMID:[Quantitative analysis of individual RNA in preparations of poly(A)+-RNA mammalian cells]. 128 8

In this study, structural changes of the p53 gene in primary specimens of human colorectal carcinomas were analyzed by polymerase chain reaction mediated-DNA sequencing method. Point mutations of p53 gene, including an intronic mutation case, were detected in 8 of 14 carcinomas (57%). Point mutations of the gene were also observed in 2 of 2 adenomas, suggesting that mutations occur prior to the carcinoma stage. These results support that p53 gene plays an important role in the development of colorectal cancer. The frequency of Ki-ras oncogene mutations was also studied by polymerase chain reaction-single strand conformation polymorphism analysis (PCR-SSCP). This resulted in the rate of 42% (10/24), a quite similar value obtained by other methods. As PCR-SSCP analysis is a convenient method to detect point mutation, we have now examined 24 colorectal cancers for the p53 gene by this method, and detected the mutations. Furthermore, expression of the DCC gene, a candidate of tumor suppressor gene involved in colorectal carcinogenesis, was examined by reverse transcriptase-mediated PCR (RT-PCR) assay, resulting in significant reduction on the DCC expression in 8 of 14 carcinoma cases (57%).
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PMID:Mutations of the p53 gene and other genes involving in human colorectal carcinogenesis. 130 99

The detection of human papillomavirus (HPV) type 16 early genes: E7, E5, and the late gene: L1 was attempted in 42 uterine cervical neoplasia (35 cervical carcinomas and 7 cervical dysplasias) using the polymerase chain reaction (PCR) method. Consequently, E7 gene was detected in 19 (54.3%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, E5 gene was detected in 7 (20.0%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, L1 gene was detected in 18 (51.4%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, respectively. In order to elucidate the transcriptional pattern of HPV type 16 in each of the clinical stages, the expression of mRNA for E7, E5 and L1 genes was examined in HPV DNA positive cases using the reverse transcriptase polymerase chain reaction (RT-PCR) method. E7 gene mRNA was detected in 18 (94.7%) of 19 cervical carcinomas, whereas E5 and L1 genes mRNAs were detected in only 4 (57.1%) of 7 and in one (5.6%) of 18 carcinomas respectively. In cervical dysplasias, E7, E5 and L1 genes mRNA were detected in all cases. E7, E5 and L1 genes were transcriptionally active in all dysplasias, whereas E5 and L1 genes were not always transcriptionally active in carcinomas. These results suggest that the HPV type 16 early gene E7 is present preferentially as integrated form and transcriptionally active in the carcinoma cell, and plays an important role in the development of malignancy. On the other hand, E5 and L1 genes are present and transcribed in the dysplasia cell but their transcriptional activity is less frequent in the carcinoma cell.
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PMID:Occurrence and expression of human papillomavirus type 16 genes in uterine cervical carcinomas. 133 65

Retrovirus-like particles were secreted in a steroid-dependent manner by the human mammary carcinoma cell line T47D. The particles exhibited typical retroviral properties such as their electron microscopic appearance (95 nm in diameter) and occasional budding, sedimentation at 1.14 g/ml, reverse transcriptase activity and genomic RNA. The T47D particles were related to mouse mammary tumour virus (MMTV) as shown by their ultrastructural appearance (B type-like eccentric dense cores and budding), Mg2+ dependence of the reverse transcriptase activity; immunological reactivity with MMTV-directed antibodies (revealing proteins of 63K, 52K, 26K and 18K), and hybridization of particle RNA with MMTV DNA under stringent conditions. Purified particles were able to incorporate deoxynucleoside triphosphates in the absence of an exogenous primer and template, thus indicating the existence of a complete and biochemically functional reverse transcription apparatus (reverse transcriptase, RNA and primer) and the ability to direct endogenous cDNA synthesis. Labelled particle cDNA hybridized strongly to human genomic DNA but not to mouse and cat DNA, thus indicating the human origin of the T47D particles. Furthermore all human DNAs, hybridized with the labelled particle cDNA, showed a uniform hybridization pattern of restriction fragments, indicating the endogenous origin and distribution of the proviral particle DNA in the human genome.
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PMID:Retrovirus-like particles from the human T47D cell line are related to mouse mammary tumour virus and are of human endogenous origin. 137 76

A full length cDNA whose corresponding mRNA is down-regulated during the mouse embryonic brain development was isolated. The cDNA contains a single long open reading frame which could encode a protein with relative molecular mass of 41 kDa. The predicted gene product contains long stretches of prolines towards the NH2-terminus, followed by a leucine/proline rich region. The cDNA probe detected a number of mRNA species in Northern blot analysis. The reverse transcriptase-polymerase chain reaction analysis of mRNA from adult mouse tissues indicated that heart and testis expressed this gene (named NDPP-1) at relatively high levels, while lower levels of mRNA were detected in a number of other tissues. Expression of NDPP-1 was also detected in embryonic carcinoma and pheochromocytoma cell lines, but not in fibroblasts. The cDNA hybridized to genomic DNA from several vertebrates species in Southern blot analysis indicating interspecies conservation of this gene. The interesting pattern of expression of the NDPP-1 gene during mouse brain development and the structure of its putative protein product indicate that this gene may play an important biological role in the development of mouse central nervous system.
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PMID:Identification of a developmentally regulated gene in the mouse central nervous system which encodes a novel proline rich protein. 142 Mar 3

The hormone gastrin is mainly produced by the G cells of the antral mucosa and plays a major role in the regulation of digestive mucosal growth. Since it permits identification of cell types containing mRNA, in situ hybridization (ISH) appears to be an interesting method for studying gastrin-producing tissues. In this study, in situ detection of gastrin mRNA has been carried out on frozen sections of four human normal antral mucosa samples and of six colonic carcinomas removed from patients with high levels of plasma gastrin, using a gastrin oligonucleotidic DNA probe. We have compared the results provided respectively by the [35s] labelling and the digoxigenin labelling of the synthetic probe. Positive cells were found in each normal sample analysed with radioactive- as well as digoxigenin-labelled antisense probes. The total number of cells expressing gastrin mRNA appeared slightly higher with the [35s]-labelled probe, while the digoxigenin-labelled probe gave a better definition of positive signals. In contrast, neither radioactive nor cold probes gave positive signals in the six colonic carcinoma samples, although gastrin expression had been demonstrated in these tumours using a reverse transcriptase-PCR method. These results show that, although ISH does not seem sensitive enough to allow the detection of very low levels of gastrin expression, it would appear to be a reliable method for visualizing gastrin mRNA in human antral mucosa.
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PMID:Detection of gastrin mRNA by in situ hybridization using radioactive- and digoxigenin-labelled probes: a comparative study. 144 1


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