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)

The expression of cystic fibrosis transmembrane conductance regulator (CFTR) in the thyroid has not been documented to date, although a role for CFTR in the thyroid follicular epithelium is suggested both clinically, by the occurrence of subclinical hypothyroidism in patients with cystic fibrosis (CF), and physiologically, by the presence of low-conductance, adenosine 3',5'-cyclic monophosphate-activated Cl channels in the follicular cells. Using reverse transcriptase-polymerase chain reaction with nested primers derived from exons 13 and 14 of the human CF gene, we have now documented the presence of CFTR mRNA in the human thyroid. Western blot analyses using six antibodies directed against different domains of human CFTR showed that a 165-kDa band was present in membrane extracts from bovine and human thyroid. This protein has the predicted size of mature CFTR and was not detected with preimmune serum or preadsorbed antiserum. By immunofluorescence and immunoperoxidase, CFTR was located in the follicular cells, with a diffuse, intracellular labeling pattern. Quantitative analysis revealed that 64% of the follicles were CFTR positive, but only 16% of the follicular cells were stained per follicle. The number of CFTR-positive cells was inversely proportional to the size of the follicle. These results 1) demonstrate the expression of CFTR at the mRNA and protein levels in human and bovine thyroid follicular cells and 2) suggest that CFTR expression could be instrumental in follicular enlargement.
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PMID:Expression of CFTR in human and bovine thyroid epithelium. 914 56

The aims of this study were to establish whether both the cystic fibrosis (CF) and multidrug resistance (MDR1) genes are expressed in the human placenta during development and differentiation. To study their pattern of expression during development, RNA was extracted from first, second and third trimester human placentas. To investigate differentiation, RNA was extracted from cytotrophoblast cells isolated from human term placentas and maintained in culture for 18, 66, 90 and 114 h and from the undifferentiated choriocarcinoma cell line JAr. Using the reverse transcriptase-polymerase chain reaction (RT-PCR) with gene specific, intron spanning primers, a cDNA product of 1 kb, as expected for CF expression, was detectable following 35 cycles of PCR from all RNA samples except those from JAr; in the latter a product was only detected in one sample out of four separate passages and this was only just detectable after 40 cycles of PCR. RT-PCR using MDR1 specific primers resulted in a product from all samples at 0.34 kb as expected if this gene is expressed. These results demonstrate that both the CF and MDR1 genes are expressed in the human placenta at all stages of development and differentiation, although the expression of the CF, but not the MDR1, gene appears to be much weaker in the undifferentiated JAr cells in comparison with cytotrophoblast cells.
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PMID:Expression of the cystic fibrosis (CF) and multidrug resistance (MDR1) genes during development and differentiation in the human placenta. 923 84

Patients with cystic fibrosis develop lung disease after birth, therefore CFTR gene replacement therapy should be most efficacious in the neonatal period prior to the onset of pulmonary damage. An adeno-associated virus (AAV) vector, SA306 (Flotte TR et al Proc Natl Acad Sci USA 1993; 90: 10613-10617), which contains the AAV inverted terminal repeats flanking the human CFTR cDNA linked to an amino-terminal epitope tag, was used to transduce a human CFTR fusion protein into neonatal New Zealand white rabbits. Vector inocula of 1 x 10(5) to 5 x 10(10) particles were given by intratracheal instillation on day 3 of life and the rabbit lungs were studied at 3 or 4 days, 2-6 weeks, or 6 months after infection; the 2-6 week time-point corresponds to the completion of the alveolar phase of lagomorph lung development. Vector DNA was detected by an in situ polymerase chain reaction (PCR) using vector-specific primers at up to 6 weeks after inoculation. Human CFTR mRNA was detected by Northern analysis at up to 2 weeks after vector inoculation, and by a reverse transcriptase PCR assay at up to 3 weeks after infection. Epithelial expression of the human CFTR fusion protein was detected using antisera to both the human CFTR R domain and the amino-terminal epitope at up to 6 weeks after vector inoculation. Vector DNA, mRNA, or human CFTR immunoreactivity were not observed at the 6 month time-point. Rabbits infected with SA306 were clinically indistinguishable from their uninfected litter mates. These data indicate that CFTR gene transduction using an AAV vector is feasible in the neonatal rabbit, and that expression of vector-derived CFTR persists throughout the alveolar phase of lung development. The apparent lack of vector persistence after the alveolar phase may reflect dilution of transduced cells by further lung growth or a lack of transduction of pulmonary epithelial stem cells.
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PMID:CFTR gene transduction in neonatal rabbits using an adeno-associated virus (AAV) vector. 927 14

Human tracheal gland (HTG) serous cells are now believed to play a major role in the physiopathology of cystic fibrosis. Because of the persistent inflammation and the specific infection by Pseudomonas aeruginosa in the lung, we looked for the action of the lipopolysaccharide (LPS) of this bacteria on human tracheal gland cells in culture by studying the secretion of the secretory leukocyte proteinase inhibitor (SLPI) which is a specific serous secretory marker of these cells. Treatment with Pseudomonas aeruginosa LPS resulted in a significant dose-dependent increase in the basal production of SLPI (+ 250 +/- 25%) whilst the SLPI transcript mRNA levels remained unchanged. This LPS-induced increase in secretion was inhibited by glucocorticoides. Furthermore, LPS treatment of HTG cells induces a loss of responsiveness to carbachol and isoproterenol but not to adenosine triphosphate. These findings indicate that HTG cells treated by Pseudomonas aeruginosa LPS have the same behavior as those previously observed with CF-HTG cells. Exploration by using reverse transcriptase polymerase chain reaction amplification showed that LPS downregulated cystic fibrosis transmembrane conductance regulator (CFTR) mRNA expression in HTG cells indicative of a link between CFTR function and consequent CF-like alteration in protein secretory process.
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PMID:Pseudomonas aeruginosa lipopolysaccharide induces CF-like alteration of protein secretion by human tracheal gland cells. 942 67

We have previously characterized the expression of the cystic fibrosis transmembrane conductance regulator protein (CFTR) gene, mRNA and protein in rat brain with reverse transcriptase (RT)-PCR amplification, in situ hybridization and immunocytochemistry. We now report that the CFTR mRNA is expressed in the human anterior hypothalamus, an area involved in regulation of appetite, resting energy expenditure and sexual differentiation. Expression of CFTR in neurons localized to this region may elucidate the pathogenesis of other non-pulmonary manifestations of cystic fibrosis which commonly are observed in children with CF, including congenital absence of the vas deferens. Neuron-specific expression of CFTR in brain may be involved in the regulation of homeostatic functions including reproductive function and fertility through effects on neurosecretion, i.e. GnRH release. Dysregulation of normal neuropeptide vesicle trafficking by mutant CFTR in brain my lead to alteration in physiological function.
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PMID:Cystic fibrosis transmembrane conductance regulator expression in human hypothalamus. 959 64

Cystic fibrosis (CF) is an inherited disorder associated with severe inflammation and repeated bacterial infection and colonization in the lung. Airway epithelium is involved in defence against bacteria, but this system may be defective in CF. Pro-inflammatory cytokines can stimulate the expression of inducible nitric oxide synthase (iNOS), an enzyme generating nitric oxide, which functions as an important mediator in host defence mechanisms. To understand better the poor resistance to infections in the CF lung, the expression of the iNOS gene was investigated in explanted lungs from patients with cystic fibrosis (n = 13), bronchiectasis (n = 3), emphysema (n = 14), and in normal lungs (n = 8). In addition, bronchial epithelial cell lines were examined to study iNOS gene expression in vitro. Strong immunoreactivity for iNOS was seen in inflammatory cells and bronchial epithelium in all the diseased lungs, except for bronchial epithelium in CF. Quantitative analysis showed a significant reduction in the area of epithelium immunostained in CF [CF 6.8 +/- 1.6 (% +/- SEM); emphysema 18.2 +/- 2.8; normal 9.6 +/- 0.8, P < 0.01], regardless of steroid treatment. These results were supported by in situ hybridization of iNOS mRNA, which showed a pattern of gene expression in CF, emphysema, and normal lung which paralleled that of protein immunoreactivity. Stimulation with cytokines (IL-1 beta, TNF-alpha, and IFN-gamma) increased the expression of iNOS mRNA detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in cultures of normal (16HBE14o-), but not CF (CFBE41o-, with delta F508 CFTR mutation) epithelial cells. Expression of iNOS in inflammatory cells suggests that the gene is normal in CF. Absence of iNOS from bronchial epithelium may be due to low expression of the gene resulting from abnormalities in the signalling system that normally causes induction, such as cytokine receptors, second messengers or transcription factors. The resulting deficiency of the nitric oxide defence system may be relevant to the susceptibility of CF patients to pulmonary bacterial colonization.
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PMID:Lack of inducible nitric oxide synthase in bronchial epithelium: a possible mechanism of susceptibility to infection in cystic fibrosis. 961 86

Cystic fibrosis (CF) is characterized by defective Cl- and enhanced Na+ conductance, both due to malfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in airway epithelial cells. In the present study we examined whether expression of CFTR mRNA (CFTR messenger ribonucleic acid) is different in airway epithelia derived from either CF patients or healthy volunteers. Moreover, we tried to correlate differences in epithelial Cl- and Na+ conductance with the level of CFTR mRNA expression and studied whether these properties correlate to the clinical phenotype of CF patients. To that end, CFTR mRNA was determined by means of quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and cyclic adenosine monophosphate (cAMP)-activated Cl- and epithelial Na+ conductances were examined in airway epithelial cells using microelectrode techniques. Complementary in vitro data were obtained from cultured CF and non-CF airway epithelial cell lines. Genotype and Shwachman score were assessed for each patient. We found variable levels of CFTR mRNA expression in airway cells of both CF patients and healthy volunteers. As expected, epithelial Na+ conductance was enhanced and CFTR Cl- conductance was absent in airway cells from CF patients. However, CFTR mRNA expression did not correlate with either electrophysiological properties or Shwachman scores obtained from CF patients. In addition, CFTR mRNA expression did not correlate to Cl- conductance in cultured CF and non-CF airway epithelial cells. These results indicate a lack of correlation between levels of CFTR mRNA and CFTR function, and that only small amounts of CFTR are required for expression of the CFTR Cl- conductance.
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PMID:Lack of correlation between CFTR expression, CFTR Cl- currents, amiloride-sensitive Na+ conductance, and cystic fibrosis phenotype. 1023 Sep 24

We report the cloning of a murine ClC-2 chloride channel cDNA from duodenal epithelium by reverse transcriptase-polymerase chain reaction (RT-PCR) using degenerate primers and by rapid amplification of cDNA ends (RACE)-PCR. Other than CFTR, this represents the first cloned chloride channel from intact intestine. The ClC-2 cDNA predicts encoding of a 908 amino acid polypeptide with a calculated M(r) of 99,373. The amino acid sequence of the murine ClC-2 chloride channel is over 94% identical to the ClC-2 chloride channel proteins of other species. Of interest is the finding that the ClC-2 mRNA is expressed about the same level in duodena from both CFTR knockout and wild-type mice. This is in keeping with the suggestion that ClC-2 might be a therapeutic target in cystic fibrosis.
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PMID:Cloning of ClC-2 chloride channel from murine duodenum and its presence in CFTR knockout mice. 1052 21

In patients with cystic fibrosis (CF), the progression of pulmonary disease differs considerably, even in identical cystic fibrosis transmembrane conductance regulator-genotypes which could reflect an additional influence of the host's immune response. This study therefore measured cytokine expression patterns in CF patients with different clinical presentation. Expression of interleukin (IL)-8, interferon gamma (IFN-gamma), IL-4, IL-10, and transforming growth factor (TGF)beta(I) was assessed in bronchial mucosal biopsies of eight CF patients with acute exacerbation (age 6.0-14.2 yrs), eight CF patients with chronic stable disease (age 7.3-17.4 yrs), and in five normal control subjects by semiquantitative and quantitative reverse transcriptase polymerase chain reaction combined with histopathological assessment and immunohistochemical staining. All CF patients expressed IL-8. In acute exacerbation, expression of TGF-beta1 and IFN-gamma was either absent or extremely low. In contrast, all patients with stable disease strongly expressed TGF-beta1. The highest expression of TGF-beta1 and IFN-gamma was found in CF patients with mild disease and a history of infrequent exacerbations. No correlation was found between the expression of IL-4 and IL-10 and patient history. In normal control subjects, only a weak expression of TGF-beta1 was observed. These results show a remarkable correlation between cytokine pattern and the clinical course of cystic fibrosis. High expression of transforming growth factor-beta1 and interferon gamma was associated with mild disease, whereas no or very weak expression of these cytokines was typical for patients with acute disease and frequent exacerbations suggesting a contribution of the immune response to the progression of pulmonary disease in cystic fibrosis.
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PMID:Cytokine expression in bronchial biopsies of cystic fibrosis patients with and without acute exacerbation. 1059 3

Recent evidence has shown that the inducible form of nitric oxide (NO) synthase (NOS2) has reduced expression in airway epithelia of patients with cystic fibrosis (CF) despite the presence of chronic inflammation. The goal of this paper is to determine whether NOS2 expression is regulated by the presence of functional CF transmembrane conductance regulator (CFTR). Using a human trachea epithelial cell line in which CFTR activity is blocked by the overexpression of the CFTR regulatory domain, we found that loss of CFTR activity reduces NOS2 messenger RNA expression as determined by reverse transcriptase/polymerase chain reaction and reduces overall NO production compared with mock-transfected controls. An in vivo model using mice lacking CFTR expression (cftr -/-), wild-type mice (cftr +/+), and cftr -/- mice that have had human CFTR introduced to the intestinal epithelium using the fatty acid binding protein (FABP) promoter (FABP-hcftr) was also examined. Electrical characterization confirmed that FABP-hcftr mice had corrected electrophysiologic properties compared with cftr -/- mice in the ileum, but FABP-hcftr nasal transepithelial potential difference measurements were identical to cftr -/- values showing specific intestinal correction. NOS2-specific immunostaining revealed that NOS2 expression is evident in sections of ileum and nasal epithelium of cftr +/+ mice but is absent in both tissues in cftr -/- mice. FABP-hcftr mice, however, show strong NOS2 staining in epithelial cells of the ileum but reduced staining in the nasal epithelium, suggesting a CFTR-related influence in the regulation of NOS2 expression in epithelial cells.
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PMID:Cystic fibrosis transmembrane conductance regulator-dependent regulation of epithelial inducible nitric oxide synthase expression. 1061 64


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