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)

Partial sequences were derived for the 16S-like ribosomal RNA of Halteria grandinella, Glaucoma chattoni, Colpidium campylum, Opisthonecta henneguyi and Colpoda inflata. Using isolated bulk nucleic acid preparations, partial rRNA sequences were determined using a series of oligonucleotide primers complementary to conserved sequence elements of the molecule and a dideoxynucleotide sequencing reaction using reverse transcriptase. Sequences were aligned and an evolutionary tree was generated by a distance-matrix method, comparing these partial sequences to the complete sequences of species of Tetrahymena, Paramecium, Euplotes, Oxytricha and Stylonychia. Halteria shows greater similarity to the stichotrichs Oxytricha and Stylonychia than to the hypotrich Euplotes, while these four genera share the same branch. Glaucoma and Colpidium appear closely related to Tetrahymena, with all three being more closely related to Opisthonecta than to Paramecium. Colpoda diverges near the base of the branch shared by Paramecium and the four oligohymenophorean genera. These results are discussed with reference to published revisions of the systematics of the phylum Ciliophora.
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PMID:Assessment of phylogenetic relationships among ciliated protists using partial ribosomal RNA sequences derived from reverse transcripts. 245 7

Lymphoma was diagnosed in a 7-year-old domestic cat found to be infected with FeLV and feline immunodeficiency virus (FIV). The cat was affected by chronic disorders suggestive of immunosuppression, including gingivitis, periodontitis, keratitis, and abscesses. Despite treatment, peripheral keratitis of the left eye progressed, resulting in uveitis, chronic glaucoma, and eventual corneal rupture. Microscopic retinal and optic disk pathologic processes also were suspected. Abnormal jaw movements that were believed to be indicative of neurologic disease were observed. Approximately 17 months later, the cat developed generalized lymphadenopathy, hepatosplenomegaly, and bilateral renomegaly. Lymphoblastic lymphoma and glomerulonephritis were diagnosed histologically. Manganese- and magnesium-dependent reverse transcriptase activity were detected in supernatants from lymph node and spleen mononuclear cell cultures, suggesting T-lymphocyte infection with FeLV and FIV.
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PMID:Feline leukemia virus and feline immunodeficiency virus infections in a cat with lymphoma. 253 74

Telomerase, an essential ribonucleoprotein reverse transcriptase, adds telomeric DNA to the ends of eukaryotic chromosomes. We examined the conformational properties of the naked RNA moiety of telomerase from two related ciliates, Tetrahymena thermophila and Glaucoma chattoni. As well as finding evidence for features proposed previously on the basis of phylogenetic comparisons, novel conserved structural properties were revealed. Specifically, although the region around helix III was previously proposed to form a pseudoknot, our results indicate that in the naked RNA this region maintains a level of 'plasticity', probably in an equilibrium favoring one of two helices. In addition, these studies reveal that the templating domain is not entirely single-stranded as previously proposed, but is ordered due to constraints imposed by other parts of the RNA. Finally, our results suggest that the GA bulge in helix IV may introduce a structurally conserved kink. We now propose a 'two-domain' structure for the telomerase RNA based on function: one conformationally flexible domain, which includes the template and the region around helix III, involved with enzymatic function, and a second largely helical domain, including helices I and IV and the proposed kink, which may serve as a scaffold for protein binding.
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PMID:Architecture of telomerase RNA. 798 68

By using the techniques of reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern hybridization, we demonstrated that human Tenon's capsule fibroblasts in primary cultures, express the messenger RNA (mRNA) transcripts encoding transforming growth factor-beta 1 (TGF-beta 1), basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF), but not those coding for aFGF and TGF-beta 2. Two PCR products were obtained for TGF-beta 1: a major fragment of 161 base pairs that corresponded to the expected size, and a minor sequence of 400 base pairs. An antisense oligonucleotide probe specific for TGF-beta 1 detected only the band of 161 base pair of PCR-amplified sequence. For bFGF, PDGF-A and PDGF-B, we obtained only a single PCR product with the anticipated length of 222, 225, and 217 base pairs, respectively. Southern blotting experiments revealed that these PCR-amplified fragments were specific for the respective growth factors. The negative control experiments without template did not reveal any amplification. No product for aFGF or TGF-beta 2 was detected. By radioimmunoassay, TGF-beta 1 protein was detected at the level of 24-30 pg ml-1 per 2 million Tenon's fibroblasts during a 24-hour period in acid-activated conditioned medium. These results indicate that human Tenon's capsule fibroblasts in primary cultures express TGF-beta 1 at the translational as well as at the transcriptional levels, and they also have the capacity to synthesize bFGF and PDGF. Considering the significant effects of bFGF, TGF-beta 1, and PDGF in wound healing response, these growth factors are implicated in tissue repair process after glaucoma filtration surgery that contributes to the failure of the procedure.
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PMID:Expression of growth factor mRNAs by human Tenon's capsule fibroblasts. 894 7

Telomerase is a ribonucleoprotein reverse transcriptase that synthesizes and maintains telomeric DNA. Studies of telomeres and telomerase are facilitated by the large number of linear DNA molecules found in ciliated protozoa, such as Tetrahymena thermophila. To examine the expression of telomerase, we investigated the transcription of the RNA polymerase III-directed gene encoding the RNA subunit (TER1) of this enzyme. A chimeric gene containing the Glaucoma chattoni TER1 transcribed region flanked by 5' and 3' Tetrahymena regions was used to identify promoter elements following transformation of Tetrahymena cells. Disruption of a conserved proximal sequence element (PSE) located at -55 in the Tetrahymena TER1 5' flanking region eliminated expression of the chimeric gene. In addition, mutation of an A/T-rich element at -25 decreased expression markedly. A gel mobility shift assay and protein-DNA cross-linking identified a PSE-binding polypeptide of 50-60 kDa in Tetrahymena extracts. Gel filtration analysis revealed a native molecular mass of approximately 160 kDa for this binding activity. Our results point to a similar architecture between ciliate telomerase RNA and metazoan U6 small nuclear RNA promoters.
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PMID:Identification of an essential proximal sequence element in the promoter of the telomerase RNA gene of Tetrahymena thermophila. 1051 20

Type 1B astrocytes of the human optic nerve head (ONH) constitutively express neural cell adhesion molecule (NCAM) in vivo and in vitro. Increased synthesis of NCAM has been detected in reactive astrocytes in the glaucomatous ONH of human donor eyes. Several NCAM isoforms are generated through alternate RNA splicing in tissue- and disease-specific patterns. In this study, we analyzed expression of NCAM isoforms in ONH of normal donors at different ages and in glaucoma. Total RNA was extracted from ONH of fetal, normal adult and glaucomatous eyes, and cultured human ONH astrocytes, fetal brain astrocytes and an astrocytoma cell line, for reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. To distinguish between NCAM 180 and 140 isoforms, exon-specific primer sets covering exons 13-19 were used. Isoform-specific riboprobes were used for in situ hybridization (ISH) in glaucomatous and in age-matched ONH. By RT-PCR, NCAM 140 was the predominant isoform in adult ONH as well as in all cultured cells. NCAM 180 mRNA was strongly expressed in glaucoma, whereas in normal adult tissues it was not detectable. ISH confirmed expression of NCAM in normal adult ONH and localized NCAM 140 mRNA to astrocytes. ISH demonstrated expression of NCAM 180 mRNA in reactive astrocytes in glaucomatous ONH. Our results demonstrate that the NCAM 180 isoform is induced in glaucoma. NCAM 180 may play a role in astrocyte interaction with extracellular matrix (ECM), vessels, axons and other astrocytes and, through its expanded cytoplasmic domain, serve as a signaling molecule for reactive astrocytes during remodeling of the ONH in glaucoma.
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PMID:Differential expression of neural cell adhesion molecule isoforms in normal and glaucomatous human optic nerve heads. 1064 Jun 77

The purpose of the present study was to establish a rat retinal ganglion cell line by transformation of rat retinal cells. For this investigation, retinal cells were isolated from postnatal day 1 (PN1) rats and transformed with the psi2 E1A virus. In order to isolate retinal ganglion cells (RGC), single cell clones were chosen at random from the transformed cells. Expression of Thy-1 (a marker for RGC), glial fibrillary acidic protein (GFAP, a positive marker for Muller cells), HPC-1/syntaxin (a marker for amacrine cells), 8A1 (a marker for horizontal and ganglion cells) and neurotrophins was studied using reverse transcriptase-polymerase chain reaction (RT-PCR), immunoblotting and immunocytochemistry. One of the retinal cell clones, designated RGC-5, was positive for Thy-1, Brn-3C, Neuritin, NMDA receptor, GABA-B receptor, and synaptophysin expression and negative for GFAP, HPC-1, and 8A1, suggesting that it represented a putative RGC clone. The results of RT-PCR analysis were confirmed by immunocytochemistry for Thy-1 and GFAP. Upon further characterization by immunoblotting, the RGC-5 clone was positive for Thy-1, negative for GFAP, 8A1 and syntaxin. RGC 5 cells were also positive for the expression of neurotrophins and their cognate receptors. To establish the physiological relevance of RGC-5, the effects of serum/trophic factor deprivation and glutamate toxicity were analyzed to determine if these cells would undergo apoptosis. The protective effects of neurotrophins on RGC-5 after serum deprivation was also investigated. Apoptosis was studied by terminal deoxynucleotidyl transferase-mediated fluoresceinated dUTP nick end labeling (TUNEL). Serum deprivation resulted in apoptosis and supplementation with both BDNF and NT-4 in the growth media, protected the RGC-5 cells from undergoing apoptosis. On differentiation with succinyl concanavalin A (sConA), RGC-5 cells became sensitive to glutamate toxicity, which could be reversed by inclusion of ciplizone (MK801). In conclusion, a transformed rat retinal cell line, RGC-5, has certain characteristics of retinal ganglion cells based on Thy-1 and Brn-3C expression and its sensitivity to glutamate excitotoxicity and neurotrophin withdrawal. These cells may be valuable in understanding of retinal ganglion cell biology and physiology including in vitro manipulations in experimental models of glaucoma.
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PMID:Characterization of a transformed rat retinal ganglion cell line. 2431 44

The present study was conducted to assess the effect of Tranilast, a drug developed as anti-keloid and anti-hypertrophic scar agent, on the level of transforming growth factor- A1 (TGF- A1) mRNA, and on TGF- A1 secretion in Chang Conjunctiva cells. TGF- A1 mRNA was not detected in Chang Conjunctiva cells by Northern blot analysis, but reverse transcriptase-polymerase chain reaction (RT-PCR) analysis confirmed the presence of TGF- A1 mRNA. Tranilast, whereas the drug had no effect on the levels of TGF- A1 mRNA and cellular protein, time- and dose-dependently inhibited TGF- A1 secretion from Chang Conjunctiva cells in the enzyme-linked immunosorbent assay (ELISA) analysis. TGF- A1 is suggested to cause fibroblast proliferation, that obstructs aqueous humor filtration route after glaucoma filtration surgery. Tranilast, potentially inhibiting TGF- A1 secretion, therefore, could be a promising drug to prevent from scarring after glaucoma filtration surgery.
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PMID:Tranilast inhibits TGF- A1 secretion without affecting its mRNA levels in conjunctival cells. 1178 98

Several prostaglandin analogues used for glaucoma treatment have been shown to cause increased iridial pigmentation as side-effect. In the present study we identified the types of prostanoid receptors and cyclooxygenase (COX) enzymes that are expressed in human iridial melanocytes isolated from eyes of different colours. Iris specimens were obtained during trabeculectomy surgery, or from enucleated eyes, and the iridial melanocytes were isolated and cultivated. The transcription of the DP, EP1, EP2, EP3, EP4, FP, IP and TP prostanoid receptor genes as well as the COX-1 and COX-2 enzyme genes was investigated using reverse transcriptase-polymerase chain reaction (RT-PCR). Of the prostanoid receptors the FP receptor gene was found to be most consistently transcribed in the melanocytes isolated from both blue- and hazel-coloured eyes. No RNA of the DP, EP2 and TP receptor genes could be detected, whereas the EP1, EP3, EP4 and IP receptor genes were found to be transcribed in melanocytes from some eyes. The COX-2 gene was found to be transcribed, but the COX-1 gene less consistently. There was no difference in gene transcription pattern between melanocytes originating from eyes treated with latanoprost, and eyes not previously treated with the prostaglandin. These results indicate that the FP prostanoid receptor gene is transcribed in cultivated human iridial melanocytes of both blue and hazel eyes, whereas the other prostanoid receptor genes seem to be transcribed much less frequently, or not at all. Surprisingly, the COX-2 rather than the COX-1 gene, was found to be transcribed in the melanocytes.
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PMID:Transcription of prostanoid receptor genes and cyclooxygenase enzyme genes in cultivated human iridial melanocytes from eyes of different colours. 1251 24

Whether cultured bovine trabecular meshwork cells and trabecular tissue ex vivo express insulin-like growth factor-I (IGF-I) messenger RNA (mRNA) and protein was investigated. Total RNA of cultured bovine trabecular meshwork cells as well as trabecular meshwork tissue freshly excised from bovine eyes was extracted, and reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect IGF-I mRNA. RT-PCR product was verified by sequencing. Immunohistochemical stain was used to detect IGF-I protein. The results showed that a single PCR amplified product was obtained, and the sequence was homologous to the known sequence.. IGF-I immunostain was positive in the cytoplasm of trabecular meshwork cells. It was concluded that trabecular meshwork cells produce IGF-I and contribute to the presence of IGF-I in trabecular meshwork microenvironment as well as aqueous humor. Trabecular meshwork cells were affected by IGF-I not only through paracrine, but also autocrine action. Whether abnormal down-regulations in IGF-I production may contribute to the pathogenesis of primary open-angle glaucoma and the possibility of promoting the autocrine action of IGF-I by trabecular meshwork cells to treat the disease is worth further investigation.
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PMID:Insulin-like growth factor-I gene cloning and protein expression in bovine trabecular meshwork tissue and cells. 1265 89


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