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)

Telomerase is a cellular endogenous reverse transcriptase thought to play an important role in the maintenance of telomere length. We investigated the effects of 3'-azido-2',3'-dideoxyguanosine (AZddG) and carbocyclic oxetanocin G (C.OXT-G), of which the triphosphate derivatives AZddGTP and C.OXT-GTP show potent telomerase inhibition, on telomere length of human HL60 cells in culture. Although AZddG caused more significant telomere shortening than C.OXT-G, only a slight decrease of cell growth rate was observed.
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PMID:Telomere shortening in human HL60 cells by treatment with deoxyguanosine analogs. 1715 May 41

Oxidation of RNA precursors may disturb genetic information by mispair formations. In this study, effects of oxidized ribonucleoside triphosphates on in vitro transcription catalyzed by T7 RNA polymerase were examined. 8-Hydroxyguanosine 5'-triphosphate (8-OH-GTP) and 2-hydroxyadenosine 5'-triphosphate (2-OH-ATP) reduced amount of RNA. In addition, mRNA was converted to cDNA by reverse transcriptase, and the cDNA was then amplified by PCR. The PCR product was subsequently cloned into plasmid DNA and sequence of DNA was analyzed for each bacterial colony. The two oxidized ribonucleotides induced mutations in cDNA, suggesting disturbance of genetic information during transcription and/or reverse transcription. 8-OH-GTP induced T-->G plus T-->C mutations and 2-OH-ATP caused T-->C mutations. These results indicate that formation of these oxidized RNA precursors in cells affects transcription quantitatively and qualitatively. In addition, they are potential antiviral drugs that cause mutations in genomic RNA.
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PMID:Mutagenic properties of oxidized GTP and ATP in in vitro transcription-reverse transcription. 1715 Aug 36

Oxidation of RNA precursors may disturb genetic information. In this study, the effects of oxidized RNA precursors on in vitro transcription were examined. Two oxidized ribonucleoside triphosphates, 8-hydroxyguanosine 5'-triphosphate (8-OH-GTP) and 2-hydroxyadenosine 5'-triphosphate (2-OH-ATP), were added to in vitro transcription reactions. The addition of 8-OH-GTP and 2-OH-ATP reduced the amount of RNA synthesized in vitro. Moreover, to examine qualitative alteration of the mRNA, it was converted to cDNA by reverse transcriptase, and the cDNA was then amplified by PCR. The PCR product was subsequently cloned into plasmid DNA, and the DNA sequence was analyzed for each bacterial colony. The two oxidized ribonucleotides induced mutations in cDNA, suggesting the disturbance of genetic information during transcription and/or reverse transcription. 8-OH-GTP induced T-->G plus T-->C mutations, and 2-OH-ATP caused T-->C mutations. These results indicate that the formation of these oxidized RNA precursors in cells affects transcription quantitatively and qualitatively.
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PMID:Effects of 8-hydroxy-GTP and 2-hydroxy-ATP on in vitro transcription. 1766 47

Gastrodia elata Blume (GEB) is an important medicinal plant in Korea. In order to confirm the anti-tumor activities of GEB extracts, we carried out various in vitro anti-tumor assays, including a wound assay and an invasion assay using an ethyl ether extract of GEB. The results showed that the GEB extract exhibits potent anti-tumor activity in vitro in a dose-dependent manner. The expression of CD44, cdc42, Timp-2 or RhoA mRNA did not change by GEB treatment, compared to that of the control. GTP-Ras, an active form of a G-coupled protein family, however, is associated with the anti-tumor activity of GEB extracts. We examined various molecular markers related to metastasis by reverse transcriptase-polymerase chain reaction with the extract of GEB-treated B16 cells. There was an increase in GTP-Ras expression by the Gastrodia elata Blume extract. Together, these results suggest that the Gastrodia elata Blume extract could have potential in alleviating tumorigenesis, by a GTP-Ras-dependent pathway; although the precise molecular mechanisms are still being examined.
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PMID:Anti-tumor activity of Gastrodia elata Blume is closely associated with a GTP-Ras-dependent pathway. 1778 45

Experimental evidence indicated that interferon-inducible guanylate-binding proteins (GBPs) are similar with genes in the myxovirus (Mx) resistance protein subfamily of the large GTPases protein family and play important roles in the resistance to intracellular pathogens. As more diseases exert significant influence on pig industry, it is anticipated that more candidate disease-resistance genes could be found in future strategies aimed at improving genetic resistance to infectious diseases. In this study, we cloned cDNA sequences and analyzed the genomic structure of porcine GBP1 (poGBP1) and GBP2 (poGBP2). The two genes were mapped to SSC4q21-q23 and SSC4q24 by the SCHP panel respectively, further IMpRH panel analysis showed both genes were most closely linked to the marker SWR153. The deduced amino acid sequences of these two genes share the same three classical GTP-binding motifs at the amino terminus and are less conserved at the carboxyl termini except for a CaaX motif, compared with human and mouse counterparts. The reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that poGBP1 and poGBP2 were both widely expressed in many tissues, and transient transfection indicated that poGBP1 and poGBP2 proteins were both located in cytoplasms within Pig Kidney Epithelial cells (PK15). Quantitative real-time PCR (Q-RT-PCR) analyses showed poGBP1 and poGBP2 had very similar expression patterns in PK15 cells at different time points after poly I:C stimulation, suggesting that ISRE (interferon-stimulated response element) plays a crucial role in the transcriptional regulation of these two genes. Four single nucleotide polymorphisms (SNPs) and three SNPs were detected in the cDNA sequences of poGBP1 and poGBP2, respectively. Association analyses revealed that the poGBP1 Eco81I and poGBP2 SspI polymorphisms both had significant associations (p<0.05) with red blood cell count (RBC), haemoglobin concentration (HGB) and hematocrit (HCT) of 17-day-old pigs.
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PMID:Molecular characterization of the porcine GBP1 and GBP2 genes. 1834 89

The complete coding sequences of three porcine genes Rho-related GTP-binding proteins RHOB and RHOG and Prenylated Rab acceptor protein 1 (PRAF1) were amplified using the reverse transcriptase polymerase chain reaction based on the sequence information of the mouse or other mammals and referenced highly homologous pig ESTs. The nucleotide sequences of these three genes revealed that porcine RHOB gene encodes a protein of 196 amino acids that contains the conserved putative RhoA-like domain and has high homology with the RHOB precursor of human, rat and mouse (100%).The porcine RHOG gene encodes a protein of 191 amino acids that contains the conserved putative RhoG domain and has high homology with the RhoG precursor (RHOG) of human, mouse and Cricetus cricetus (98%). The porcine PRAF1 gene encodes a protein of 185 amino acids that contains the conserved putative PRA1 domain and has high homology with the PRAF1 of dog (97%), cattle (97%), human (96%), rat (95%) and mouse (95%). The tissue expression analysis indicated swine RHOB gene was moderately expressed in lung, weakly in fat, spleen, kidney, and almost not expressed in small intestine, large intestine, liver, muscle. The swine RHOG gene was over-expressed in small intestine, large intestine, liver, and muscle, moderately expressed in kidney, weakly in spleen, and almost not expressed in fat and lung. The swine PRAF1 gene was over-expressed in fat and spleen, moderately in lung and kidney, weakly in small intestine and large intestine, and almost not expressed in liver and muscle.
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PMID:[Cloning, nucleotide sequence and tissue expression profile of three novel porcine genes--RHOB, RHOG and PRAF1]. 1838 20

The biocompatibility of nanoparticles is the prerequisite for their applications in biomedicine but can be misleading due to the absence of criteria for evaluating the safety and toxicity of those nanomaterials. Recent studies indicate that mesoporous silica nanoparticles (MSNs) can easily internalize into human mesenchymal stem cells (hMSCs) without apparent deleterious effects on cellular growth or differentiation, and hence are emerging as an ideal stem cell labeling agent. The objective of this study was to thoroughly investigate the effect of MSNs on osteogenesis induction and to examine their biocompatibility in hMSCs. Uptake of MSNs into hMSCs did not affect the cell viability, proliferation and regular osteogenic differentiation of the cells. However, the internalization of MSNs indeed induced actin polymerization and activated the small GTP-bound protein RhoA. The MSN-induced cellular protein responses as believed to cause osteogenesis of hMSCs did not result in promotion of regular osteogenic differentiation as analyzed by cytochemical stain and protein activity assay of alkaline phosphatase (ALP). When the effect of MSNs on ALP gene expression was further examined by reverse transcriptase polymerase chain reaction, MSN-treated hMSCs were shown to have significantly higher mRNA expression than control cells after 1-hour osteogenic induction. The induction of ALP gene expression by MSNs, however, was absent in cells after 1-day incubation with osteogenic differentiation. Together our results show that the internalization of MSNs had a significant effect on the transient protein response and osteogenic signal in hMSCs, thereby suggesting that the effects of nanoparticles on diverse aspects of cellular activities should be carefully evaluated even though the nanoparticles are generally considered as biocompatible at present.
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PMID:Internalization of mesoporous silica nanoparticles induces transient but not sufficient osteogenic signals in human mesenchymal stem cells. 1851 41

Little is known about the G protein-coupled receptor desensitization process during pregnancy. Wistar pregnant rats were treated with (-)N(6)-phenylisopropyladenosine (R-PIA), an adenosine A(1) receptor (A(1)R) agonist, in their drinking water during pregnancy, and the effect on A(1)R/adenylyl cyclase system was studied in both maternal and fetal brain. In maternal brain, binding assays revealed a significant decrease in total receptor numbers in plasma membranes (27%, P<0.05), with no significant changes in receptor affinity. The effect of R-PIA on plasma membranes from fetal brains was more marked, with approximately 42% (P<0.05) of the total receptors detected in control fetuses. Real time reverse transcriptase polymerase chain reaction (RT-PCR) analyses showed that chronic R-PIA treatment during the whole gestational period only decreased significantly mRNA level coding A(1)R in maternal brain (P<0.05). alpha Gi(1,2) and alpha Gi(3) subunits were not affected in mothers or fetuses as revealed by immunoblotting. mRNA levels coding these subunits were also unaffected in mothers and fetuses. On the other hand, forskolin- and forskolin-plus guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S)-stimulated adenylyl cyclase activity was decreased in maternal (P<.01) and fetal brain (P<.001). Furthermore, adenylyl cyclase inhibition elicited by N(6)-cyclohexyladenosine (CHA), a selective A(1)R agonist, was significantly decreased in both maternal (P<0.05) and fetal brain (P<.01), suggesting a desensitization of the A(1)R/adenylyl cyclase pathway. Therefore, these results suggest that R-PIA intake during pregnancy causes desensitization of the A(1)R-mediated inhibitory transduction pathway in both maternal and fetal brain, probably due to the decreased density of A(1)R at the cell surface.
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PMID:Reduced expression and desensitization of adenosine A1 receptor/adenylyl cyclase pathway after chronic (-)N6-phenylisopropyladenosine intake during pregnancy. 1955 60

A 55-year-old man sought care for aggressive acute lymphoblastic leukemia (ALL), which developed 8 years after he had received chemotherapeutic treatment for nephrotic syndrome. The sole cytogenetic abnormality observed in bone marrow-derived metaphases was a t(4;11)(q21;q23), which is a frequently occurring translocation in ALL. However, subsequent reverse transcriptase-polymerase chain reaction for the expected mixed lineage leukemia [trithorax homolog, Drosophila] (MLL)-AFF1 fusion transcript was negative. Further fluorescence in situ hybridization (FISH) analysis narrowed the 4q21 breakpoint down to a 250-kb region proximal of AFF1. This comprised four genes, of which septin11 (SEPT11) was further analyzed. Reverse transcriptase-polymerase chain reaction revealed expression of a chimeric MLL-SEPT11 transcript, thus identifying what is to our knowledge a hitherto undescribed translocation in ALL. Sequence analysis of cDNA showed in-frame fusion of MLL exon 11 to SEPT11 exon 2. This MLL-SEPT11 fusion is cytogenetically indistinguishable from the recurrent t(4;11)(q21;q23). Thus, it is crucial to characterize cytogenetic aberrations in leukemia by molecular methods, even in cases where a known recurrent translocation is presumed. This report expands the spectrum of ALL-related translocations and hypothesizes on the mechanism leading to the MLL-SEPT11 fusion. Five septins have been identified thus far as MLL fusion partners in leukemia. Their putative oncogenic role may be related to forced MLL dimerization by the septin coiled coil and GTP-binding domains, which could convert MLL to an oncogene.
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PMID:A translocation in acute lymphoblastic leukemia that cytogenetically mimics the recurrent MLL-AFF1 translocation and fuses SEPT11 to MLL. 2063 69

Telomerase is a key participant of telomere length maintaining system in the majority of eukaryotes. It synthesizes telomere repeats at the 3'-end of telomere DNA using its own RNA template. The Saccharomyces cerevisiae telomerase complex contains the reverse transcriptase (Est2) and RNA subunits (TLC1), as well as number of additional proteins among which Est3 is known to be essential for telomere length maintenance. We have found that Est3 can hydrolyze GTP in vitro and investigated parameters of this reaction. The data obtained suggest that Est3 may function as unusual GTPase in vivo.
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PMID:Yeast telomerase protein Est3 is a novel type of GTPase. 2088 18


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