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

---

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

A total of 81 cell clones persistently infected with the LAV-1 or HTLV-IIIB strain of human immunodeficiency virus type 1 (HIV-1) was isolated from cells which were obtained by serial passage of some proliferating MT-4 cells after a drastic cytolysis of most cells by HIV-1-infection. These cell clones were classified into 8 types (I to VIII) in terms of the expression of HIV-1 antigens, syncytium formation capacity, and reverse transcriptase activity and infectivity of virus particles in the culture fluid. Type I cell clones were producers of infectious HIV-1 particles, while types II to VIII cell clones did not produce infectious HIV-1 or were producers of uninfectious defective HIV-1 particles. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis (PAGE) showed that the gag precursor protein in L-2 cell clone (type IV) was not cleaved to mature gag proteins, while the env precursor protein on L-3 cell clone (type III) was not cleaved to mature env protein. H-7 cell clone (type VIII) did not express any HIV-1 antigen. All these cell clones after the superinfection with infectious HIV-1 synthesized intact gag and env proteins, which were, at least in part, related to the HIV-1 genome persistently present in the cell clones before the superinfection, resulting in production of infectious HIV-1. For example, it was found that L-2 cell clone contained a single copy of the LAV-1 genome per haploid cell and produced doughnut-shaped particles. On the other hand, the cell clone isolated from the L-2 cell clone superinfected with infectious HTLV-IIIB contained the integrated HTLV-IIIB genome in addition to the LAV-1 genome present before the superinfection, and produced intact HIV-1 particles in addition to doughnut-shaped particles from a single cell. These results indicate that complementation and/or genetic recombination events in the superinfected cells may account for the production of infectious intact HIV-1 virions.
...
PMID:Production of infectious particles from defective human immunodeficiency virus type 1 (HIV-1)-producing cell clones by superinfection with infectious HIV-1. 200 Nov 75

Open reading frame (ORF) VIII of cauliflower mosaic virus (CaMV) was analyzed by site-directed mutagenesis in order to investigate its potential function for the viral life cycle. Removal of either the start or the stop codon of ORF VIII, as well as interruption of ORF VIII by a new stop codon, did not affect infectivity. Unlike certain ORF VII mutants all three ORF VIII mutants are stable. Hence the ORF VIII product is not essential and ORF VIII mutations do not have deleterious polar effects on the expression of the downstream ORF V, which codes for the viral protease/reverse transcriptase.
...
PMID:Open reading frame VIII is not required for viability of cauliflower mosaic virus. 234 69

Protoberberine alkaloids such as palmatine (I), 13-methylpalmatine iodide (II), 2,3-methylenedioxy-10,11-dimethoxy-13-methylprotoberberine iodide (III), 2,3-methylenedioxy-9,10-dimethoxy-13-methylprotoberberine chloride (IV), and berberine (V) showed inhibition of reverse transcriptase activity of RNA tumor viruses in the presence of polyriboadenylic acid-oligodeoxythymidylic acid (VI), polydeoxyadenylic acid-oligodeoxythymidylic acid (VII), activated calf thymus deoxyribonucleic acid (IX), and 70S ribonucleic acid (X), but not in the presence of polyribocytidylic acid-oligodeoxyguanylic acid (VIII). These results indicated that the alkaloids caused inhibition of the enzyme activity by interacting with the template primer, particularly of the adenine-thymine base pair. Furthermore, the alkaloids competed with the template primer-binding site of the enzyme. The time course inhibition indicated that the alkaloids stopped the DNA synthesis instantly when added after the initiation of polymerization processes. Inhibition of reverse transcriptase activity was correlated with the structure and antileukemic activity of the protoberberine alkaloids.
...
PMID:Enzyme inhibition VI: Inhibition of reverse transcriptase activity by protoberberine alkaloids and structure-activity relationships. 619 Oct 21

Hormonal regulation of the expression of mRNA transcripts for cAMP response element-binding protein (CREB) and cAMP response element modulator (CREM) during spermatogenesis was studied in the adult rat testis. Northern analysis of CREB and CREM identified two mRNA transcripts for CREM (2.4 and 1.6 kb) and one transcript for CREB (2.0 kb). Analysis of mRNAs from isolated testicular cells by reverse transcriptase polymerase chain reaction (RT/PCR) showed that CREM mRNAs were expressed by the germ cells but not the Sertoli or interstitial cells, whereas CREB mRNA was located in germ cells, Sertoli cells, and interstitial cells. RNA was isolated and analyzed from the testes of 1) rats treated for 24 h with FSH, 2) rats in which androgen withdrawal had been induced by ethane dimethane sulphonate (EDS) treatment 6 days earlier (EDS-treated), 3) EDS-treated rats supplemented with testosterone (EDS + T), or 4) intratesticular administration or dibutyryl cAMP (dbcAMP) in the preceding 24 h. CREM mRNA transcript expression was found to be decreased after all of these treatments in samples from intact testis and from isolated cells. Expression of the CREB transcript was also decreased by EDS-induced androgen withdrawal, but not by FSH or EDS + T. In situ hybridization of paraffin-embedded testis sections probed with digoxigenin-labeled riboprobes confirmed the localization of CREB and CREM mRNA to the same cell types as found with RT/PCR. No stage-dependent expression of CREM mRNA transcripts could be observed. Hybridization of the CREB probe was highest around the base of stage VII-VIII tubules, and this was shown to be androgen-dependent. The data presented suggest that regulation of the expression of CRE-binding protein mRNAs in Sertoli and germ cells during spermatogenesis is dependent on both androgen and FSH. However, the effects of androgen or FSH on the regulation of CRE-binding protein mRNAs are different.
...
PMID:Differential regulation of cyclic adenosine 3',5'-monophosphate (cAMP) response element-binding protein and cAMP response element modulator messenger ribonucleic acid transcripts by follicle-stimulating hormone and androgen in the adult rat testis. 751 86

Radiation-induced gene expression was examined in rat astrocyte cultures using differential display of mRNA via reverse transcriptase-polymerase chain reaction. A 0.3-kb cDNA that was consistently observed in irradiated cultures but not in unirradiated cultures was cloned and sequenced. It was found to be identical to Ptk-3, a receptor tyrosine kinase gene identified recently. The protein encoded by Ptk-3 is a member of a novel class of receptor tyrosine kinases whose extracellular domain contains regions of homology with coagulation factors V and VIII and complement component C1. Northern blot analysis revealed that the expression of Ptk-3 was increased in rat astrocytes by 0.5 h after exposure to 10 Gy and remained at the same elevated level for at least 24 h. The maximum increase occurred after 5 Gy. Cloning studies indicated the presence of at least two Ptk-3 mRNA transcripts, which are probably the result of an alternative splicing mechanism. The short isoform lacks a 37-amino acid sequence in the glycine/proline-rich juxtamembrane region. The splicing pattern of the Ptk-3 gene was not altered by radiation. However, the ratios of the longer to the shorter mRNA transcripts differed between adult cortex, neonatal cortex and in vitro astrocyte cultures.
...
PMID:Radiation induction of the receptor tyrosine kinase gene Ptk-3 in normal rat astrocytes. 759 35

As dendritic antigen-presenting cells in skin and mucous membranes, Langerhans cells (LC) are found in areas at risk of inoculation by the human immunodeficiency virus (HIV). LC have been reported as targets for HIV-1. The aim of the present study was to investigate whether LC can be experimentally infected by HIV provided by a cell-free infection system. A cell-free suspensions was prepared from viral particles provided by chronically infected cell lines (U937 or H9 cells) by low-speed centrifugation followed by 0.45-microns filtration. LC-enriched epidermal cell (EC) suspensions with no CD3+ cells (assessed by flow cytometry and electron microscopy) and uninfected U937 cells (cell-free infection system control) were infected with two isolates (HTL VIII-B and RF). The infectiousness of the cell-free virus fluids was controlled on U937 cells where proviral DNA was amplified (gag, pol, and env gene sequences by the polymerase chain reaction, PCR) and release of virus particles into the supernatant was controlled either by measure of the reverse transcriptase (RT) activity or detection of viral RNA amplified by RT-PCR for the gag gene sequences). Proviral DNA (gag gene sequences) was found in LC-enriched epidermal cellular DNA from day 4 post-infection with isolate HTL VIII-B and from day 7 with isolate RF. Although the RT activity did not reach a significantly high level, viral RNA was found in the supernatant of LC-enriched EC cultures at the same time as proviral DNA was detected in LC.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Detection of HIV-specific DNA sequences in epidermal Langerhans cells infected in vitro by means of a cell-free system. 772 34

Renal injury in diabetes mellitus is associated with progressive interstitial fibrosis and extracellular matrix accumulation. However, the phenotypes of cells forming the interstitial infiltrate in diabetic nephropathy have not been precisely defined. There is increasing evidence for the association of mast cells with angiogenesis, chronic inflammatory conditions and fibrosis. We have recently shown that human mast cells can produce the non-fibrillar short chain type VIII collagen in vivo. Using immunohistochemistry, in situ hybridisation and reverse transcriptase-polymerase chain reaction, we examined the contribution of mast cells and type VIII collagen to the fibrotic changes occurring in biopsy-proven diabetic nephropathy. We observed that the number of interstitial mast cells was significantly increased in diabetic nephropathy compared with normal kidney tissue. In specimens from diabetic subjects, intense immunohistochemical staining for type VIII collagen was detected in mast cells, on periglomerular fibres and in perivascular and interstitial sites. The expression of type VIII collagen in periglomerular and interstitial sites coincided with that of alpha smooth muscle actin, a marker for myofibroblastic differentiation mRNA for type VIII collagen was detected by reverse transcriptase-polymerase chain reaction in diabetic nephropathy and in a human mast cell line. By in situ hybridisation the transcripts for type VIII collagen were localised to renal mast cells. The increased number of mast cells and the elevated type VIII collagen deposition in human diabetic nephropathy provides a potential link between the extracellular matrix accumulation and the fibrosis observed in this condition.
...
PMID:Mast cells and type VIII collagen in human diabetic nephropathy. 889 10

Type VIII collagen is a short-chain collagen with considerable similarity to type X collagen. We have generated chain-specific antibodies to the alpha 1 and alpha 2 chains of type VIII collagen, and used them as probes to examine the synthesis of type VIII collagen by vascular smooth muscle cells (VSMC). In addition, chain-specific oligonucleotides have been used in reverse transcriptase-PCR (RT-PCR) reactions with RNA extracted from cultured smooth muscle cells in culture and from freshly isolated vascular tissues. Radiolabelling of VSMC in culture and immunoprecipitation with chain-specific antibodies showed that both chains were expressed. Lower levels of type VIII collagen were found in adult VSMC than in neonatal VSMC. RT-PCR showed that both chains were expressed in tissues as well as cells in culture. The results indicate that type VIII collagen is a product of VSMC of normal adult vessels and is expressed at high levels by VSMC in vascular lesions.
...
PMID:Type VIII collagen is a product of vascular smooth-muscle cells in development and disease. 892 Oct 10

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.
...
PMID:Infection of primary human placental fibroblasts with HIV-1, HIV-2, and SIV. 967 89

A simple and rapid single-step reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the nucleoprotein (N) gene of 11 rabies viruses. A conserved set of RT-PCR primers was designed to amplify the most variable region in the N gene. N gene regions were amplified from 6 fixed laboratory viruses, 4 street viruses from dogs in Thailand, and a horse in Zambia. Sequences of the amplified products, together with the database of 91 additional sequences, were analyzed by using PILEUP program of the GCG package. The rabies viruses grouped into at least 9 distinct clusters by < 90% nucleotide similarity of the N gene region: I (4 isolates, USA), II (2 isolates, South America), III (3 isolates, Africa), IV (52 strains, Europe, Middle East, Africa and South America), V (16 isolates, North America and Arctic), VI (17 isolates, Africa), VII (1 isolate, Africa), VIII (6 isolates, Thailand and Malaysia) and IX (1 isolate, Sri Lanka). A unique group of rabies viruses from Thailand and clusters of isolates corresponding to their geographic origin also were determined. The simple and rapid single-step RT-PCR proved to be useful for identifying rabies viruses, and for grouping the viruses into clades by sequence analysis.
...
PMID:Nucleoprotein gene analysis of fixed and street rabies virus variants using RT-PCR. 967 37


1 2 Next >>

---