Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The unusual hypotonicity of equine blastocyst fluid has prompted us to investigate the role of sodium- and potassium-dependent adenosine triphosphatase (Na+,K+-ATPase) in the process of fluid accumulation in the horse conceptus. Nine mares were used for the experiments. Reverse transcriptase polymerase chain reaction was conducted on two sets of five conceptuses recovered between 12 and 28 days (+/- 1 day) after ovulation. Messenger RNAs encoding the alpha1 and beta1 subunit isoforms of Na+,K+-ATPase were detected in all embryonic tissues examined. Western blot analysis showed that alpha1 and beta1 subunits are both present in Day 15 conceptuses. Trophoblast tissues from 19 conceptuses between 8 and 31 days after ovulation were stained immunohistochemically using primary antibodies against the alpha1 and beta1 subunit isoforms of the Na+,K+-ATPase. Both isoforms were detected in all sections. Trophoblastic vesicles, prepared from 6 conceptuses between 12 and 14 days after ovulation, were used to investigate the inhibition of blastocyst expansion with ouabain after collapse induced with cytochalasin D. In normal medium there was a mean 3-fold increase, and in ouabain (10(-6) M) a mean 3-fold decrease, in the volume of vesicles that had been partially collapsed with cytochalasin D. We therefore conclude that, despite the hypotonicity of the blastocyst fluid in the early horse conceptus, the Na+,K+-ATPase plays a role in its accumulation, as in other species.
 ...
PMID:Evidence for the presence of sodium- and potassium-dependent adenosine triphosphatase alpha1 and beta1 subunit isoforms and their probable role in blastocyst expansion in the preattachment horse conceptus. 928 1

Arsenic compounds, Including arsenic trioxide (As2O3) and arsenic sulfide (As4S4), have recently been shown to be effective in the treatment of acute promyelocytic leukemia (APL). In vitro, As2O3 exerts a dose-dependent dual effect: it triggers apoptosis at relatively high concentrations (0.5 to 2.0 micromol/L) and induces partial differentiation at low concentrations (0.1 to 0.5 micromol/L). The apoptosis-inducing effect is associated with the collapse of mitochondrial transmembrane potentials in a thiol-dependent manner, whereas the retinoic acid signaling is required for APL cell differentiation. As2O3 over a wide range of concentrations (0.1 to 2.0 micromol/L) Induces degradation of PML-RARalpha as well as the wild-type PML and enhances the acetylation of histone, a process important for the transcriptional activation of genes. In vivo, As2O3 induces a high complete remission (CR) rate in patients with both primary and relapsed APL (around 85% to 90%). Side effects, such as skin reaction, gastrointestinal symptoms, electrocardiographic (EKG) changes, neuropathy, and liver dysfunction, are mild to moderate in relapsed patients, and severe hepatic lesions have been found in some primary cases. After CR obtained in relapsed patients, chemotherapy in combination with As2O3 as postremission therapy has yielded better survival than treatment with As2O3 alone. This is in line with the observation that remission induction with As2O3 is not sufficient in most cases to obtain a molecular remission as Judged by reverse-transcriptase polymerase chain reaction for PML-RARalpha fusion transcripts. The in vivo effect of As2O3 seems to be related to the expression of APL-specific PML-RARalpha oncoprotein, and a synergistic effect between As2O3 and ATRA has been shown in the APL mouse model. Besides As2O3, other arsenic compounds such as As4S4 also show a therapeutic effect in APL. Because the toxic effects of arsenic treatment in primary APL need to be investigated further, we propose use of ATRA as a first-line drug for remission induction in primary APL, whereas As2O3 can be incorporated into multidrug postremission therapy or used as rescue for relapsed APL patients.
 ...
PMID:Treatment of acute promyelocytic leukemia with arsenic compounds: in vitro and in vivo studies. 1117 37

Two open reading frames at the 5'-end of the tomato bushy stunt virus genomic RNA are predicted to encode a 33-kDa (p33) protein and its 92-kDa (p92) readthrough product. From amino acid sequence comparisons with other small single-stranded RNA viruses, these proteins resemble viral components of the replicase-transcriptase complex. To investigate the accumulation of these proteins in the infected cell, two chimeric proteins were produced that expressed either a portion of p33 or the carboxy-terminal "half" of p92 fused with glutathione S-transferase, and polyclonal ascites fluids specific to p33 or p92 were elicited in mice. As expected, the anti-p33 antibody recognized p33 and the p92 readthrough protein, but the anti-p92 antibody was specific for p92. Immunoblot analyses revealed that at an early stage of infection both proteins were associated with the membrane fractions isolated from virus-infected plants, but later in the infection, prior to collapse of the tissues, these proteins were also associated with the cytoplasmic fraction. At all time points in plants and protoplasts p33 was about 20-fold more abundant than p92. A series of mutations derived from an infectious cDNA clone demonstrated that both the p33 and the p92 proteins were required for replication in protoplasts and the ratio of the two proteins was maintained in the replication-competent mutants. The wild-type amber (UAG) and in vitro-generated ochre (UAA) readthrough codon derivatives replicated in protoplasts. However, the tyrosine mutants (UAC or UAU) that were predicted to express only p92 were not viable in protoplasts.
 ...
PMID:The tomato bushy stunt virus replicase proteins are coordinately expressed and membrane associated. 1183 21

Using poliovirus (PV) and its RNA-dependent RNA polymerase (RdRp) as our primary model system, we have advanced knowledge fundamental to the chemistry and fidelity of nucleotide addition by nucleic acid polymerase. Two fidelity checkpoints exist prior to nucleotide addition. The first toggles the enzyme between a nucleotide binding-occluded state and a nucleotide binding-competent state. The second represents an ensemble of conformational states of conserved structural motifs that permits retention of the incoming nucleotide in a state competent for phosphoryl transfer long enough for chemistry to occur. Nucleophilic attack of the alpha-phosphorous atom of the incoming nucleotide produces a pentavalent transition state, collapse of which is facilitated by protonation of the pyrophosphate leaving group by a general acid. All of the relevant conformational states of the enzyme are controlled by a network of interacting residues that permits remote-site residues to control active-site function. The current state of the art for PV RdRp enzymology is such that mechanisms governing fidelity of this enzyme can now be targeted genetically and chemically for development of attenuated viruses and antiviral agents, respectively. Application of the knowledge obtained with the PV RdRp to the development of vaccines and antivirals for emerging RNA viruses represents an important goal for the future.
...
PMID:Fidelity of Nucleotide Incorporation by the RNA-Dependent RNA Polymerase from Poliovirus. 2724 34

Enteroviruses generally cause mild and self-limited diseases, but they have been found to affect neonates much differently, and often more severely than older children. Clinical manifestations are difficult to differentiate from those of bacterial sepsis, such as fever, poor feeding, lethargy, respiratory distress and cardiovascular collapse. Severe life threatening complications, including hepatic necrosis with coagulopathy, meningoencephalitis and myocarditis, usually present during the first week of life. Factors affecting severity and outcome include virus serotype, mode of transmission, and presence or absence of passively acquired, serotype-specific maternal antibodies. Echoviruses and coxsackievirus B viruses are most common serotypes associated with the neonatal sepsis. An awareness of the clinical syndromes, recognition of the risk factors and monitoring parameters associated with severe cases and use of rapid reverse-transcriptase polymerase chain reaction test for viral load may help physicians in diagnosing severe cases in a timely manner. Prompt aggressive treatment including early intravenous immunoglobulin treatment may help in reducing morbidity and mortality. Enterovirus infections in neonates are common and should be routinely considered in the differential diagnosis of febrile neonates, particularly during enterovirus season. This article provides an overview of what is known about non-polio enteroviruses in neonates including epidemiology, transmission, clinical presentation, diagnosis, and treatment.
 ...
PMID:Enteroviral infection in neonates. 3160 72

Motivated by the current COVID-19 health crisis, we consider data analysis for quantitative polymerase chain-reaction (qPCR) measurements. We derive a theoretical result specifying the conditions under which all qPCR amplification curves (including their plateau phases) are identical up to an affine transformation, i.e. a multiplicative factor and horizontal shift. We use this result to develop a data analysis procedure for determining when an amplification curve exhibits characteristics of a true signal. The main idea behind this approach is to invoke a criterion based on constrained optimization that assesses when a measurement signal can be mapped to a master reference curve. We demonstrate that this approach: (i) can decrease the fluorescence detection threshold by up to a decade; and (ii) simultaneously improve confidence in interpretations of late-cycle amplification curves. Moreover, we demonstrate that the master curve is transferable reference data that can harmonize analyses between different labs and across several years. Application to reverse-transcriptase qPCR measurements of a SARS-CoV-2 RNA construct points to the usefulness of this approach for improving confidence and reducing limits of detection in diagnostic testing of emerging diseases. Graphical Abstract Left: a collection of qPCR amplification curves. Right: Example of data collapse after affine transformation.
 ...
PMID:Affine analysis for quantitative PCR measurements. 3295 Oct 64