Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Based upon our previous report indicating the presence of retrovirus-like particles in human gastric cancer cells, we analyzed the putative endogenous reverse transcriptase activity these particles should have. To evaluate the specificity of reverse transcription over that displayed by normal cellular DNA polymerases, the following discriminatory criteria were used: 1) resistance to high concentrations of Actinomycin D; 2) sensitivity to preincubation with ribonuclease A; 3) behavior in cesium sulfate isopycnic gradients and 4) size-shifting of putative template-product complexes after RNase exposure in agarose gel electrophoresis. We report a significant endogenous reverse transcriptase activity associated with membrane-encapsidated particles from terminally-illed patients but not in normal counterparts. Although these structures closely resemble retro viruses, a new model is proposed to explain our findings.
Cell Mol Biol (Noisy-le-grand) 1992 Nov
PMID:Further characterization of RNA-dependent-DNA polymerase activity in human gastric cancer. 128 60

Insulin-like growth factor II (IGF-II) cDNA was isolated from adult guinea pig liver by polymerase chain reaction (PCR) screening. A cDNA sequence was obtained corresponding to part of the preproIGF-II, including the signal peptide, the mature IGF-II and 37 amino acids of the acid carboxy-terminal E-domain. Amino acid sequence prediction, based on the cDNA clone, showed that mature guinea pig IGF-II has a high homology with both human and rat IGF-II, 100 and 94% identity, respectively. Levels of IGF-II mRNA in guinea pigs of different ages were analyzed by solution hybridization/RNase protection assay using part of the isolated IGF-II cDNA as a probe. There is a marked developmental regulation of IGF-II after birth. IGF-II mRNA levels were high in fetal livers, and decreased 15- to 30-fold in adults. As in man, but in contrast to rats, adult guinea pigs have significant levels of IGF-II mRNA in the liver. In fetal guinea pigs, the expression of IGF-II mRNA was 5-, 2- and 70-fold lower in kidney, skeletal muscle and brain cortex, respectively, than in liver. IGF-II mRNA levels in kidney and skeletal muscle of fetal guinea pigs were 5- and 4-fold higher, respectively, compared with adults. Similar sizes of IGF-II mRNA transcripts could be observed on Northern blots in newborn rats and in fetal guinea pigs. Our conclusions are that the mature IGF-II peptide in the guinea pig is 100% identical to the mature peptide in the human.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Endocrinol 1992 Nov
PMID:Isolation of an insulin-like growth factor II cDNA from guinea pig liver: expression and developmental regulation. 130 79

Steady state levels of the mRNA coding for the neurotransmitter biosynthetic enzyme, acetylCoA-choline-O-acetyltransferase (ChAT, EC 2.3.1.6), were measured in wild type Drosophila and two temperature-sensitive mutants (Chats1 and Chats2) using the RNase protection method. At a permissive temperature the relative amounts of ChAT mRNA were: wild type: Chats1:Chats2 = 1:2.09 (+/- 0.39):3.37 (+/- 0.57) (mean +/- S.E.M.) indicating that mutant flies may compensate, for making a thermolabile form of enzyme, by producing and/or maintaining higher levels of ChAT mRNA. At a restrictive temperature the ChAT mRNA levels decreased in both mutants and increased in wild type flies. The regulatory mechanism(s) responsible for increasing ChAT mRNA in wild type flies appears to have failed in the mutants at high temperature. Steady state mRNA levels were also measured in embryonic cell cultures prepared from wild type embryos. Cultures grown in the presence of two pharmacologic agents (carbamylcholine and d-tubocurarine) which should interfere with cholinergic neurotransmission, showed less mRNA resulting from a decrease in levels of ChAT gene transcription. Our results imply that neurotransmission and the rate of neurotransmitter biosynthetic enzyme gene transcription are coupled for the cholinergic system in Drosophila.
Brain Res Mol Brain Res 1992 Apr
PMID:Positive and negative feedback regulation of choline acetyltransferase mRNA levels in Drosophila: a study using temperature-sensitive mutants and embryo cell cultures. 131 95

The distribution and cell localization of a pancreatic-like ribonuclease (RNAase) in the rat brain has been studied by RNA blot analysis and in situ hybridization using as a probe the cDNA coding for the rat pancreas RNAase, and by immunocytochemistry using an antiserum raised against the rat pancreas RNAase. RNA blot analysis and in situ hybridization experiments have shown that the RNAase mRNA is present in all the cerebral areas investigated and that neurons appeared to be actively expressing RNAase mRNA while glial cells were devoid of hybridization signals. In agreement with these results the immunocytochemical analysis has shown that neurons are specifically immunostained. These experiments demonstrate that a pancreatic-like ribonuclease is synthesized in the neurons of the rat brain.
Brain Res Mol Brain Res 1992 Jun
PMID:A pancreatic-like ribonuclease is synthesized in rat brain. 132 5

In rat pituitary GH3 cells, thyrotropin-releasing hormone (TRH) down-regulates TRH receptor (TRH-R) mRNA (Fujimoto, J., Straub, R.E., and Gershengorn, M.C. (1991) Mol. Endocrinol. 5, 1527-1532), at least in part, by stimulating its degradation (Fujimoto, J., Narayanan, C.S., Benjamin, J.E., Heinflink, M., and Gershengorn, M.C. (1992) Endocrinology 130, 1879-1884). Here we show that TRH regulates RNase activity in GH3 cells and that specific mRNA sequences are needed for in vivo regulation of TRH-R mRNA by TRH. TRH affected RNase activity in a biphasic manner with rapid stimulation (by 10 min) followed by a decrease to a rate slower than in control lysates within 6 h. This time course paralleled the effects of TRH on degradation of TRH-R mRNA in vivo. The regulated RNase activity was in a polysome-free fraction of the lysates and was not specific for TRH-R RNA. A truncated form of TRH-R RNA that was missing the entire 3'-untranslated region (TRHR-R5) was more stable than full-length TRH-R RNA (TRHR-WT). In contrast to TRHR-WT mRNA, TRHR-R5 mRNA and TRHR-D9 mRNA, which was missing the 143 nucleotides 5' of the poly(A) tail, were not down-regulated by TRH in stably transfected GH3 cells as their rates of degradation were not increased. These data show that TRH regulates RNase activity in GH3 cells, that the 3'-untranslated region bestows decreased stability on TRH-R mRNA and that the 3' end of the mRNA is necessary for regulation by TRH of TRH-R mRNA degradation. We present an hypothesis that explains specific regulation of TRH-R mRNA degradation by TRH in GH3 pituitary cells.
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PMID:Regulation by thyrotropin-releasing hormone (TRH) of TRH receptor mRNA degradation in rat pituitary GH3 cells. 132 30

Evidence suggests that medial preoptic area (MPOA) neurones containing gamma-aminobutyric acid (GABA) are modulated directly by oestrogen. We have used an alkaline phosphatase-labelled antisense oligonucleotide probe to examine glutamic acid decarboxylase67 (GAD) mRNA expression within individual cells of the MPOA, diagonal band of Broca (DBB) and parietal cortex in rats killed at noon on each day of the oestrous cycle and after ovariectomy (n = 4-5). As a fall in extracellular GABA concentrations occurs in the MPOA on the afternoon of proestrus, the GAD67 mRNA content of cells was also examined in proestrous rats at 15:00h immediately prior to the preovulatory luteinising hormone (LH) surge. The MPOA was found to have an intermediate number of GAD67 mRNA-containing cells compared with the DBB and cortex (P less than 0.01) but expressed the lowest mean hybridisation signal (P less than 0.01). The parietal cortex had significantly fewer (P less than 0.01) GAD mRNA-containing cells than either the MPOA or DBB but these contained higher mean density of signal (P less than 0.01). The hybridisation signal for GAD mRNA was abolished by either ribonuclease pre-treatment or the use of excess non-labelled probe. No significant (P greater than 0.05) differences in GAD67 mRNA were detected in animals killed at noon throughout the oestrous cycle or after ovariectomy. On the afternoon of proestrus (15:00h) there was a significant 40% reduction in mean GAD67 mRNA content within cells of only the MPOA compared with noon (P less than 0.05). The numbers of cells in the MPOA expressing GAD67 mRNA were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)
Brain Res Mol Brain Res 1992 Aug
PMID:Expression of glutamic acid decarboxylase messenger RNA in rat medial preoptic area neurones during the oestrous cycle and after ovariectomy. 132 94

Recent evidence suggests that neuropeptide Y (NPY) is an important signal in the neural circuitry that controls feeding behavior. Previously we observed that in rats entrained to 4 h daily scheduled feeding regimen (SFR), NPY content and release in the paraventricular nucleus (PVN) was elevated but decreased rapidly in association with food consumption. In the present study, we investigated the pattern of hypothalamic NPY gene expression in SFR rats before and after food consumption by measuring the content of preproNPY mRNA in the medial basal hypothalamus (MBH). Adult male rats were maintained on either ad libitum diet (control) or on SFR. Rats were killed before food presentation at 11.00 h and at the end of 4 h food consumption at 15.00 h. The levels of preproNPY mRNA in the MBH were determined by solution hybridization/RNase protection assay using a cRNA probe complementary to rat NPY precursor mRNA. We observed that, as compared to that in control rats on ad libitum diet, preproNPY mRNA levels in the MBH were increased two-fold in the SFR rat at 11.00 h and remained elevated even after 4 h of food consumption. These results show a simultaneous enhancement in PVN NPY release and hypothalamic gene expression in advance of scheduled feeding time, but food intake rapidly decreases PVN NPY release and content, with little impact on hypothalamic gene expression.
Brain Res Mol Brain Res 1992 Sep
PMID:Hypothalamic neuropeptide Y gene expression in rats on scheduled feeding regimen. 133 61

In the human brain, alternative splicing of amyloid precursor protein (APP) gene transcript generates at least three types of mRNA coding for APP770, APP751 and APP695. The former two types harbor, but the latter one lacks a domain of Kunitz-type serine protease inhibitor (KPI). We studied, by using the RNase protection technique, the expression of APP mRNAs in brains of Alzheimer's disease (AD) and other neurological disorders with special reference to aging. We found that the ratio of (APP770 mRNA+APP751 mRNA)/APP695 mRNA in the frontal cortex increased approximately 1.5-fold in AD compared with other neurodegenerative or cerebrovascular disorders. The ratio in other neurological disorders did not change significantly from control even in their affected brain regions. On the other hand, we found a positive correlation between the ratio and age; the ratio (y) increased gradually with the advance of age (x) as expressed by y = 0.005x + 0.014 (r = 0.372) for the AD group, and y = 0.004x -0.037 (r = 0.486) for the non-AD group. These correlations indicate that the AD brain reached the same ratio of KPI-harboring to lacking APP mRNAs a few decades earlier than the non-AD brain in senescence. This finding of AD-specific and age-related change led us to the idea that a relative increase in KPI-harboring APPs over a KPI-lacking APP may perturb normal degradation of APPs, thereby leading to deposition of beta A4 protein as amyloid.
Brain Res Mol Brain Res 1992 Oct
PMID:Age-related changes in the proportion of amyloid precursor protein mRNAs in Alzheimer's disease and other neurological disorders. 133 85

The expression of mRNA for GABAA receptor alpha 1-subunit in mouse cerebral cortical neurons in primary culture was examined using RNA blot analysis and ribonuclease protection assay following the treatment of neurons with muscimol, a selective agonist of GABAA receptor. The level of mRNA for GABAA receptor alpha 1-subunit showed a decrease in comparison with that in non-treated cells, whereas no changes in the level of beta-actin mRNA were noted under the same experimental conditions. This muscimol-induced reduction in GABAA receptor alpha 1-subunit mRNA was counteracted by the simultaneous exposure of neurons to both bicuculline, an antagonist of GABAA receptor, and muscimol. The expression of mRNA for GABAA receptor alpha 1-subunit also showed a decline by the treatment of cells with flunitrazepam alone, an agonist of benzodiazepine receptor, and this change was also abolished by the simultaneous exposure of cells to flunitrazepam and Ro15-1788, an antagonist for central benzodiazepine receptor. These results suggest that the continuous stimulation of cerebral GABAA receptor complex may induce the reduced expression of mRNA for the receptor complex.
Brain Res Mol Brain Res 1992 Oct
PMID:Muscimol-induced reduction of GABAA receptor alpha 1-subunit mRNA in primary cultured cerebral cortical neurons. 133 88

1. We have prepared probes specific for the chicken myogenic determination genes MyoD, myogenin, myf5, and herculin and have investigated the expression of these genes in response to denervation and acute electrical stimulation in neonate chick muscle, using ribonuclease protection. 2. Upon denervation, herculin mRNA remains essentially unchanged, myf5 transcript levels approximately double, and MyoD message is up-regulated by two- to fivefold. In contrast, the message coding for myogenin, barely detectable in innervated muscle, rises dramatically (approximately 200-fold) on the second day after nerve section; in this respect it resembles acetylcholine receptor (AChR) alpha-, gamma- and delta-subunit mRNAs. Cohybridization experiments reveal that the increase in myogenin mRNA slightly precedes the rise in AChR alpha-subunit message. 3. Electrical stimulation of denervated muscle leads to an immediate decline in myogenin and AChR alpha-subunit mRNAs, with half-lives of less than an hour and approximately 4 hr, respectively; message stability measurements suggest that this is effected through a rapid shutdown of transcription. Messages coding for MyoD, myf5, and herculin decay much more slowly, as a result of slower turnover. 4. Previous experiments have indicated the involvement of a de novo induced (Tsay, H.-J., Neville, C. M., and Schmidt, J., FEBS Lett. 274:69-72, 1990) autocatalytic (Neville, C. M., Schmidt, M., and Schmidt, J., NeuroReport 2:655-657, 1991) transcription factor in the denervation-triggered up-regulation of AChR alpha-subunit expression; the denervation and electrical stimulation experiments reported here are compatible with the notion that myogenin is that factor.
Cell Mol Neurobiol 1992 Dec
PMID:Response of myogenic determination factors to cessation and resumption of electrical activity in skeletal muscle: a possible role for myogenin in denervation supersensitivity. 133 17


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