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)

Intranasal tumors (papillary adenomas or adenocarcinomas) of the ethmoid olfactory mucosa of sheep were investigated by light and electron microscopy. The fine structure of the tumor cells was characterized by the presence of numerous secretory granules. Viral particles, which were morphologically similar to a visna-maedi virus, were detected in all tumor tissues and in 3 of 4 cultures examined. The particles (about 97 nm) had an eccentrically located electron-dense core and numerous spikes on their surfaces. The RNA-dependent DNA polymerase activities in the tumor cells or the cultured cell from the tumor were greater than those in the normal intranasal tissues or the cultured cells from the choroid plexus. Viral particles similar to herpesvirus were also detected in 1 culture.
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PMID:Intranasal tumor of the ethmoid olfactory mucosa in sheep. 21 93

Our data demonstrate the use of the reverse transcriptase polymerase chain reaction (RT-PCR) technique to study mRNA expression of genes that are devoid of introns. We have developed conditions that eliminate the false positives that can result from any preexisting DNA and that could confuse the interpretation of results. This modification (DNase pretreatment under specified conditions) ensures that the product resulting from RT-PCR is due to amplification of cDNA that has been synthesized during the reverse transcriptase reaction. Our results illustrate and emphasize the importance of including both a DNase pretreatment and a minus RT control. Using this modified procedure, our data illustrate clearly the ability of this protocol to demonstrate the presence of very low levels of olfactory marker protein (OMP) mRNA in three non-olfactory rat brain regions (cerebellum, thalamus/hypothalamus and cerebral hemispheres) where OMP mRNA was previously unknown. These data confirm a prior report of the ectopic expression of OMP immunoreactivity in these locations and indicate for the first time the "illegitimate" expression of extremely low levels of OMP mRNA in a non-neural tissue. Finally, this modification of the RT-PCR procedure will now permit the study of expression of specific, rare, mRNA molecules in the absence of any prior knowledge of the structure of their genes of origin.
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PMID:Use of reverse transcriptase polymerase chain reaction to monitor expression of intronless genes. 169 61

We have used the reverse transcriptase-polymerase chain reaction technique to gain insight into the pathogenesis of encephalitis caused by Borna disease virus (BDV). RNA specific for BDV was first detected in the olfactory bulb of intranasally infected rats at 6 days postinfection (p.i.). At 14 days p.i., high levels of BDV RNA were found in all brain regions, and at 26 days p.i., BDV-specific RNA was also present in the eye, nasal mucosa, and facial skin. In the chronic phase of the disease, BDV RNA was identified in many peripheral organs but not in blood. Analysis of brain tissue for the presence of cytokine mRNAs revealed that the mRNA levels of interleukin-6 (IL-6), tumor necrosis factor alpha, and IL-1 alpha had increased sharply at 14 and 26 days p.i. These cytokine mRNAs reached maximum levels at the peak of inflammatory reactions and decreased drastically in the chronic phase of the disease. Although IL-2 mRNA was also found in normal brain, it was markedly increased in BDV-infected brain at 14 days p.i. Expression of gamma interferon (IFN-gamma) mRNA, which was not observed in normal rat brain, was detected at 14 days p.i. and reached a maximum level at 38 days p.i. IL-2 and IFN-gamma mRNA expression correlated with expression of CD4 and CD8 mRNAs, indicating that both CD4+ and CD8+ T lymphocytes are induced in the early stages of BDV infection. Since IFN-gamma and CD8 mRNA levels were still highly elevated in the chronic phase of Borna disease, it is likely that CD8+ T lymphocytes act to reduce inflammation and to ameliorate neurological signs during the chronic phase of infection.
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PMID:Kinetics of virus spread and changes in levels of several cytokine mRNAs in the brain after intranasal infection of rats with Borna disease virus. 173 Nov 17

The proteolipid protein (PLP) gene encodes for two proteins, PLP and DM-20, which are produced by alternative splicing of exon 3B. PLP is the major CNS myelin protein and is postulated to play a structural role at the intraperiod line. Its developmental expression mirrors that of CNS myelination. DM-20 predominates in the embryo and prior to myelination of the CNS and may be involved in glial cell development. The PLP gene is expressed in the PNS in which DM-20 is the predominant isoform at all ages. In this study we describe the localization of the two isoforms in the post-natal rodent PNS using immunostaining and reverse transcriptase PCR. DM-20 is present in relatively high abundance in non-myelin-forming Schwann cells and within cytoplasmic regions of myelinated internodes, particularly the paranodes and Schmidt-Lanterman incisures and also the outer Schwann cytoplasm and perinuclear cytoplasm. DM-20 is also located in the perineuronal satellite cells of spinal, cranial and autonomic ganglia and in the ensheathing cells of the olfactory nerve layer of the olfactory bulb. PLP was detected by immunocytochemistry in the perinuclear region of myelinated internodes; PCR analysis indicated small amounts of PLP mRNA in the other locations but protein was not detected by immunostaining. Neither protein was identified in compact myelin of the PNS. DM-20 is the predominant product of the PLP gene expressed in a wide variety of peripheral glia. Its presence is not correlated to a myelin-forming state. Other studies have demonstrated early embryonic expression of the PLP gene throughout the PNS and all these features support the hypothesis that any putative role for DM-20 is unrelated to myelination but may involve glial cell development.
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PMID:Expression of the proteolipid protein gene in glial cells of the post-natal peripheral nervous system of rodents. 754 2

Kallmann's syndrome (KS) is characterised by the association of anosmia and isolated hypogonadotrophic hypogonadism (IHH). Mutations of the KAL gene which is located at Xp22.3 cause X-linked KS (XKS). In this study we used the reverse transcriptase polymerase chain reaction and in situ hybridisation to examine the developmental expression of KAL in the first trimester of pregnancy, the earliest stage of human gestation examined thus far. At 45 days after fertilisation KAL mRNA was detected in the spinal cord, the mesonephros and metanephros but not in the brain. Later in gestation, at 11 weeks, the gene was expressed in the developing olfactory bulb, retina and kidney. This expression pattern correlates with the clinical findings in XKS since olfactory bulb dysgenesis with subsequent defective neural migration causes anosmia and IHH. Additionally, renal agenesis occurs in 40% of patients. Therefore this study provides strong evidence that KAL expression is required for the normal development of the olfactory bulb and kidney in the first trimester of human pregnancy.
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PMID:KAL, a gene mutated in Kallmann's syndrome, is expressed in the first trimester of human development. 754 24

Plasma membrane calcium pumps (PMCAs) play a major role in the maintenance and fine regulation of the intracellular Ca2+ concentration. Fourteen subregions of the normal human brain were carefully dissected and analyzed by reverse transcriptase-polymerase chain reaction for the distribution of mRNAs corresponding to the four known PMCA genes as well as their alternative splicing products at two previously defined 'hotspots' A and C. All PMCA genes were found to be expressed in every brain subregion; however, consistent differences were found in the distribution of alternative splice options. The four cortical regions and hippocampus were characterized by the relative preference of variants that include an entire exon at site C and lead to the expression of isoforms of the a-type. Inferior olive and olfactory bulb showed a relative preponderance of the b-form 'default' types of alternative splicing at site C, and a decrease or even the lack of 'differentiated' forms such as variants 1a and 1c. At the N-terminal splice site A, the default x-type variants were predominant in all brain regions for PMCA 1, 3, and 4. By contrast, the pattern of PMCA2 variants was the most variable, ranging from the presence of the entire set of 2x, 2w, and 2z forms in inferior olive to the almost exclusive presence of form 2z (excluding all alternatively spliced sequences) in the four cortical regions, caudate, and hippocampus. Regional differences in the PMCA splice type distribution in normal human brain may correlate with different demands on the regulation of the set-point resting Ca2+ levels in these areas. Changes in these patterns may correlate with altered physiological states of the affected regions and/or reflect an (early) sign of Ca2+ dyshomeostasis characteristic of many neurodegenerative diseases.
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PMID:Transcript distribution of plasma membrane Ca2+ pump isoforms and splice variants in the human brain. 772 25

Complementary DNA fragments encoding the prepro-salmon gonadotropin-releasing hormone ([Trp7, Leu8]GnRH, sGnRH) of the red seabream Pagrus major were amplified from mRNA of the olfactory bulbs using a reverse transcriptase-polymerase chain reaction (RT-PCR), and the full-length cDNA was cloned from a cDNA library using the PCR-amplified cDNA as a probe. The cDNA consisted of 442 bp, including an open reading frame of 270 bp which encoded the prepro-sGnRH (90 amino acid residues). The prepro-sGnRH had the same architecture as that reported in other species. It was composed of a signal peptide, sGnRH and a GnRH-associated peptide (GAP), which was connected to sGnRH by a Gly-Lys-Arg sequence. The prepro-sGnRH of the red seabream had 90% amino acid identity to the prepro-sGnRH from an African cichlid Haplochromis burtoni which belongs to the same suborder as the red seabream; however, identity was lower to the prepro-sGnRH from Atlantic salmon Salmo salar (74%) and masu salmon Oncorhynchus masou (70%). The GnRH peptide itself and the Gly-Lys-Arg sequence in the prepro-GnRH are highly conserved among vertebrates. The red seabream GAP also shows significant amino acid identity to the GAPs of the African cichlid (89%), Atlantic salmon (74%), and masu salmon (67%), but exhibits no significant identity to chicken or mammalian GAP.
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PMID:Molecular cloning of a cDNA encoding the prepro-salmon gonadotropin-releasing hormone of the red seabream. 785 23

G(olf) alpha is a G-protein originally believed to mediate signal transduction exclusively within the olfactory neuroepithelium and subsequently found to be a major stimulatory G-protein in the basal ganglia. Here we present evidence that G(olf) alpha is expressed in several other tissues. The human isoform of G(olf) alpha was isolated from two human insulinoma cDNA libraries. Comparison of the human sequence with rat G(olf) alpha shows 91% nucleotide identity (within the coding region) and 99% identity at the amino acid level. Northern and reverse transcriptase-polymerase chain reaction analyses indicated that G(olf) alpha is expressed in all human insulinomas examined thus far as well as in normal pancreatic islets. G(olf) alpha mRNA was also detected in testis, retina, brain, and liver. Western blot analysis of various mouse tissues demonstrated that the level of G(olf) alpha protein in islets is lower than that in the olfactory neuroepithelium and other parts of the brain; its expression in retina, lung, and spleen was moderately higher than that in islets, and its expression in testis approached that in olfactory neuroepithelium. G(olf) alpha was also detected by immunohistochemistry in mouse islets, human insulinomas, the epithelial lining of mouse epididymis, photoreceptor cells of mouse retina, and mouse lung alveoli. These findings suggest a role for G(olf) alpha in a diverse population of cells located outside the olfactory neuroepithelium and central nervous system.
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PMID:Human G(olf) alpha: complementary deoxyribonucleic acid structure and expression in pancreatic islets and other tissues outside the olfactory neuroepithelium and central nervous system. 824 72

In the present study, we developed a very sensitive, semiquantitative assay based on the reverse transcriptase-coupled polymerase chain reaction to measure, in a region-selective manner, mRNA expression patterns within the brain for microsomal epoxide hydrolase and several cytochrome P-450s (P-450s) known to be induced by prototypic agents in other tissues. The P-450s assessed included the polyaromatic hydrocarbon-inducible CYP1A1 and CYP1A2 systems, together with the phenobarbital-inducible P-450s, CYP2B1, CYP2B2, CYP3A1, which were examined 18 hr after a single intraperitoneal dose of the respective inducing agents. Highly region-specific patterns of expression were evident for P-450 mRNAs within the rat brain. In the control, uninduced brain, CYP1A1 mRNAs were readily detected in the striatum and in the hypothalamus, and to a lesser extent in the other regions examined. The regional pattern of expression was similar for CYP1A2; however, a major difference was noted in the olfactory bulbs, characterized by a relatively high level of CYP1A2 mRNA but correspondingly low levels of CYP1A1. Within the brain regions examined, the highest content of CYP2B1 and CYP2B2 mRNAs were present in the striatum and in the cerebellum, whereas CYP3A1 levels varied only slightly across the respective regions. In contrast to the P-450s, microsomal epoxide hydrolase mRNAs were expressed at relative homogeneous amounts throughout the brain. beta-Naphthoflavone markedly increased the CYP1A1 and CYP1A2 mRNA contents of each brain region investigated, although this agent did not affect levels of epoxide hydrolase. At 18 hr post-treatment with phenobarbital, an optimal time period for hepatic induction, brain expression was characterized by a complex pattern of effects, with increased levels noted for CYP2B1 mRNA content in the medulla oblongata, midbrain, and cortex, but decreased contents measured in the cerebellum, the hypothalamus, and the striatum. In each of these respective regions, CYP2B2 content was profoundly decreased whereas epoxide hydrolase expression was slightly increased by the same treatment. These results establish that the central nervous system actively expresses a number of different biotransformation gene products in a regional specific and inducer-dependent manner, and suggest that for tissues exhibiting low regenerative capacity, like the brain, such reactions are likely to be of critical toxicological significance.
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PMID:Regional distribution and expression modulation of cytochrome P-450 and epoxide hydrolase mRNAs in the rat brain. 824 22

The reverse transcriptase (RT)/polymerase chain reaction (PCR) methodology was used with a set of primers that corresponds to two conserved regions of the cytochrome P450s of subfamily 2C, in order to identify the members of this group of enzymes that are expressed at the RNA level in rat brain. Seven RT/PCR clones were sequenced from female brain, and four were found to code for P450 2C7 while three for P450 2C12. Using the same methodology nine RT/PCR clones were sequenced from olfactory lobes of ethanol treated male rats and three were found to code for P450 2C6, one for P450 2C11, three for P450 2C12 and two for P450 2C23. Neither ethanol administration nor hypophysectomy or growth hormone treatment had significant effects on the expression levels of these cytochromes in the brain.
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PMID:Identification of the major cytochrome P450s of subfamily 2C that are expressed in brain of female rats and in olfactory lobes of ethanol treated male rats. 832 27


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