[Mechanism of gene expression--basic transcription factor and starting mechanism of genetic transcription].
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DNA-Directed RNA Polymerases↗
Biomedical subjects
S Kitajima
Publications and source records attributed to S Kitajima.
[Twenty-eight days repeated dose toxicity test of N-(fluorodichloromethylthio)phthalimide in rats].
N-(Fluorodichloromethylthio)phthalimide (Fluor-folpet) has been widely used as an anti-mold and anti-bacterial agent. In this study, 28 days repeated-dose oral toxicity study of fluor-folpet was carried out in Slc:Wistar rats. An oral toxicity study for fluor-folpet, the twenty-eight days test, repeated-dose, oral administration, was performed as follows: Five week-old rats, male and female, 10 rats, each/group, were treated with intragastric administration of fluor-folpet with a dose of 0 (1% Sodium CMC, control), 20, 80 and 320 mg/kg, body weight. Recovery test, for 14 days after the last treatment, was examined for the control and the 320 mg/kg groups. The 320 mg/kg groups, both males and females, showed significantly reduced their body-weight gain compared with the control group. In the 320 mg/kg group, five out of 20 male rats and four out of 20 female rats died from dyspnea during the treatment period. In the female rats in the 320 mg/kg group, serum ChE level was decreased to 50% of control level and gamma-GT was increased in a dose-dependent manner, but these serum levels recovered after 14 days non-treatment period. No histopathological change, relating to the treatment, in liver was observed. Increased weight of the kidney and vacuolation in renal tubules were found in both sexes of 320 mg/kg group. Hyperkeratosis and hyperplasia of the stomach epithelium were observed at the dose more than 80 mg/kg in male, and more than 20 mg/kg in female. A supplemental study, repeated-dose, oral administration in rats carried out to examine the dyspnea revealed that severe acute toxic damages in epithelium of nasal cavity and meatus nasopharyngeus were induced by intragastric administration of fluor-folpet. Fluor-folpet is shown to be cytotoxic. In conclusion, the no-observed-effect level (NOEL) for fluor-folpet was not found under the experimental conditions employed in this repeated-dose toxicity study.
Administration, Oral↗
[Comparative studies on a single dose toxicity of microsomal Ca(2+)ATPase inhibitor, 2,5-di(tert-butyl)-1,4-hydroquinone and its related analog, mono(tert-butyl)-1,4-hydroquinone, in rats].
We performed comparative studies to determine an acute toxicity of microsomal Ca(2+)ATPase inhibitor, 2,5-di(tert-butyl)-1,4-hydroquinone (DTBHQ) and its related analog, mono(tert-butyl)-1,4-hydroquinone (MTBHQ), which are both used as antioxodants. Wistar rats, 5 weeks old, male and female, were used. By a single dose of oral administration, DTBHQ-induced LD50 values (obtained by Lorke method) in male and female rats were estimated 295.1 and 234.4 mg/kg BW, respectively, whereas each LD50 value for MTBHQ was 711.6 and 400.0 mg/kg BW, respectively. MTBHQ-induced deaths occurred from 8 to 20 minutes after administration, however, DTBHQ-induced deaths occurred more delayed from 1 to 5 days after administration. The observed toxic signs of DTBHQ included diarrhea (jelly like), prone position, lacrimation, salivation and abnormal gait (such as reluctance to walk, limping). Localized purpura and loss of the tail (perhaps as a result of necrosis) were also observed. In comparison, MTBHQ elicited prone position, panting, staggering gait and spastic gait. Without loss of the tail montioned above, dead and sacrified rats showed no remarkable changes in macroscopic examination due to exposure to both compounds.
Administration, Oral↗
Regulation of the human general transcription initiation factor TFIIF by phosphorylation.
The transcription initiation factor, TFIIF, is essential not only for the initiation of transcription but also for efficient elongation of mRNA synthesis by mammalian RNA polymerase II and is extensively phosphorylated in vivo. The possible regulation of TFIIF activity by protein phosphorylation was investigated by comparing the biochemical properties of alkaline phosphatase-treated HeLa TFIIF with those of native or bacterially expressed factor. Alkaline phosphatase treatment decreased the size of the large subunit (RAP74) of TFIIF to that of the recombinant protein but did not change the size of the small subunit (RAP30). Both the transcription initiation and elongation stimulating activities of the alkaline phosphatase-treated TFIIF decreased to 15-20% of the native form under conditions in which the amount of TFIIF was rate-limiting for transcription. Furthermore, phosphatase-treated TFIIF assembled the DBPolF complex and bound to RNA polymerase II less efficiently than the native protein. When hybrid TFIIFs were reconstituted using native or recombinant subunits, a native form of RAP74 stimulated both transcription and DBPolF complex formation activity regardless of whether native or recombinant RAP30 was used. We propose that TFIIF activity is regulated by protein phosphorylation, particularly of the RAP74 subunit. The functional role of RAP74 in assembling the preinitiation complex and modulating TFIIF activity is discussed.
Alkaline Phosphatase↗
Enhancement of bacterial transcription initiation in vitro by the 74 kDa subunit of human general transcription factor IIF (RAP74).
The human general transcription factor IIF (TFIIF) is required for an accurate transcription initiation by RNA polymerase II and shares some analogous features with the sigma subunit of bacterial RNA polymerase. As an attempt to analyze the function of TFIIF, we examined its effect on bacterial transcription in vitro. TFIIF significantly enhanced the initiation of transcription by the bacterial RNA polymerase while other general transcription factors, TATA-binding protein, TFIIB, and TFIIE, did not. The enhancement of the bacterial transcription was ascribed to the 74 kDa subunit of TFIIF (RAP74). RAP74 had an activity of enhancing the binding of the bacterial RNA polymerase to the promoter. The enhancing activity of RAP74 depended on a low molar ratio of the RNA polymerase to the template DNA. The action of RAP74 in the bacterial transcription may be related to a possible regulatory role of RAP74 in the eukaryotic transcription initiation.
Base Sequence↗
Accumulation of amyloid beta-protein precursor (APP) in Purkinje cells and increase of amino-terminal fragments of APP in cerebrum and cerebellum of aged rat brain.
In aged rat brain, amyloid beta-protein precursor (APP) is accumulated in dendrites and cell bodies of Purkinje cells as full-length or truncated APP, because dendrites and cell bodies are positively stained by antibodies against both the amino- and carboxy-termini of APP. Western blot analysis of homogenates of brains of aged and young rats showed no apparent differences except for an increase in amino-terminal fragments in cerebrum and cerebellum of aged rat. These results indicate that the expression, transport or metabolism of APP in specific regions of brains may be affected by the aging process.
Aging↗
Role of different subtypes of P2 purinoceptor on cytosolic Ca2+ levels in rat aortic smooth muscle.
The role of different subtypes of P2 purinoceptors on cytosolic Ca2+ level ([Ca2+]i) was examined in vascular smooth muscle of rat aorta. alpha beta-Methylene-ATP (P2X agonist), 2-methylthio-ATP (P2Y agonist), UTP and ATP gamma S (P2U agonists), and ATP (nonselective P2 agonist) induced a transient increase followed by a small sustained increase in [Ca2+]i in a concentration dependent manner. Among these agonists, alpha beta-methylene-ATP was the most potent. In the absence of extracellular Ca2+ (with 0.5 mM EGTA), ATP, UTP and ATP gamma S induced a transient increase in [Ca2+]i whereas alpha beta-methylene-ATP and 2-methylthio-ATP were ineffective. ATP gamma S showed the highest potency in Ca(2+)-free solution. After desensitization of P2X purinoceptor, ATP, UTP and ATP gamma S induced a rapid increase in [Ca2+]i followed by a sustained increase while alpha beta-methylene-ATP and 2-methylthio-ATP were ineffective. These results suggest that Ca2+ release from the intracellular Ca2+ store is mediated by P2U purinoceptor whereas Ca2+ influx is mediated by both P2X and P2U purinoceptors in the rat aortic smooth muscle.
Adenosine Triphosphate↗
Involvement of clathrin light chains in the pathology of Alzheimer's disease.
Clathrin, which constitutes coated vesicles, plays important roles in neuronal functions. In the brains of the patients with Alzheimer's disease, distribution of clathrin was immunohistochemically investigated using four monoclonal antibodies against clathrin light chains, LCB.1, LCB.2, X-16 and CON.1, to study the involvement of clathrin in the pathology of Alzheimer's disease. LCB.1, LCB.2, X-16, and CON.1 bind to the aminoterminus of the clathrin light chain b(LCb), to the neuron-specific insert of LCb, to the light chain a(LCa), and to LCa and LCb, respectively. In Alzheimer brains, granular staining of LCB.2 around neurons in the hippocampus was weaker or patchily defected in comparison with control brains. Some neurofibrillary tangles and neurons were intensely stained in Alzheimer brains by LCB.2, whereas neurons were weakly stained in control brains. Crowns of some senile plaques in the brains of early onset Alzheimer's disease were positively stained by LCB.2. LCB.1 supported the observations of LCB.2. Reactive astrocytes in Alzheimer brains were intensely stained by X-16. On the other hand, Western blot analysis using LCB.2 and X-16 demonstrated no apparent differences in protein amounts and molecular weights of LCa and LCb between control and Alzheimer brains. These observations demonstrated abnormal distribution of clathrin in Alzheimer brains, implying impairment of axonal transport in this disease.
Adult↗
Monoclonal antibody HML-1 reactivity with adult T-cell leukaemia/lymphoma and other lymphomas.
Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1), a causative virus of adult T-cell leukaemia/lymphoma (ATLL), is known to be transmitted by breast-feeding. Using a monoclonal antibody HML-1 which labels human intestinal intra-epithelial T lymphocytes, we have immunohistochemically examined ATLL tissues in order to evaluate the possibility that HTLV-1 infected intestinal T cells are the origin of ATLL cells. Previously this antibody was reported to react with intestinal T-cell malignant lymphomas but not with peripheral tumours, or any B-cell lymphomas. We investigated 181 patients with malignant lymphomas and found that 19 out of 113 ATLLs were positive for HML-1. T-cell malignant lymphomas excluding ATLL also reacted with HML-1 (7/24), but all the B-cell lymphomas 0/33) and non-neoplastic lymph node and skin lesions (0/10) were negative for HML-1. In patients with ATLL and other T-cell malignant lymphomas, the positivity level of HML-1 was relatively higher in stomach (3/7) and tonsil (2/6) than that in lymph nodes (15/100) and skin (8/47). We observed one HML-1 positive ATLL patient with tumour formation in the skin and lymphadenopathy and marked infiltration of the large intestine but minimal involvement of other organs. Although HML-1 was frequently expressed in gastric infiltration of ATLL, the level of positivity was too low in lymph nodes to support the hypothesis that HTLV-1 infected intestinal T cells are the origin of ATLL cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Prevention of arterial reocclusion after thrombolysis with activated protein C. Comparison with heparin in a canine model of coronary artery thrombosis.
BACKGROUND: Reocclusion of recanalized coronary arteries often limits the efficacy of coronary thrombolytic therapy in patients with acute myocardial infarction. Activated protein C (APC) is an important regulatory enzyme in hemostasis. In view of the potential of human APC as an anticoagulant and profibrinolytic agent, the effect of APC on thrombolysis with recombinant tissue-type plasminogen activator (rTPA) was studied in a canine model of coronary artery thrombosis. METHODS AND RESULTS: Continuous artery flow monitoring in the left anterior descending coronary artery of 30 anesthetized adult beagles was performed by a magnetic flowmeter. Localized thrombosis was produced in the left anterior descending coronary artery and administration of rTPA (alteplase, 0.45 mg/kg IV) was done for 30 minutes. The dogs were randomly assigned to receive one of the following intravenous adjunctive therapies: (1) control group (n = 10): human albumin at a rate of 0.83 mL/min; (2) APC group (n = 10): human plasma-derived APC (0.6 mg/kg) with human albumin as a vehicle at a rate of 0.83 mL/min; and (3) heparin group (n = 10): heparin (200 U/kg) with saline at a rate of 0.83 mL/min. Each adjunctive therapy was started simultaneously with rTPA and lasted for 60 minutes. Coronary recanalization occurred in all dogs of each adjunctive treatment group in 19.1 +/- 1.9 minutes (mean +/- SEM). In a 120-minute observation after the termination of rTPA, reocclusion developed in all the dogs in the control and heparin groups but in only 3 of the 10 dogs in the APC group (P < .002 versus control and heparin). Time from recanalization to reocclusion (minutes, mean +/- SEM) was prolonged in the APC group (103.2 +/- 14.2) as compared with the control (10.2 +/- 2.3, P < .001) and heparin (30.3 +/- 11.8, P < .002) groups. Activated partial thromboplastin time was prolonged similarly in each group after thrombolytic therapy. On the other hand, bleeding time was prolonged in only the heparin group after the treatment. Serious hemorrhagic side effects were not observed in all three groups. CONCLUSIONS: APC prevents coronary artery reocclusion after recanalization with rTPA in a canine model of coronary artery thrombosis. This finding suggests that APC may be useful as an adjunctive treatment to enhance the effects of thrombolytic therapy in patients with acute myocardial infarction.
Animals↗
Efficacy of gas purging for titanium casting.
Oxygen density in the melting atmosphere, oxygen uptake, hardness and castability of pure titanium castings were examined to evaluate the efficacy of gas purging in reducing contamination from the melting atmosphere and mold, using a newly developed titanium casting machine in which the double purging process is systematized. The adoption of a double purging operation resulted in an extremely low oxygen density in the melting atmosphere, followed by extremely low oxygen uptake in the casting when compared with the conventional titanium casting machine. When the purging operation was used, the surface hardness was markedly reduced, although there was no difference in castability. From these results, it was suggested that the newly developed titanium casting machine with the double purging operation could produce better titanium castings with less contamination due to the mold and gas impurities in melting atmosphere.
Argon↗
Protective effects of the nucleic acid components on CCL4-induced liver injury in rats.
In our previous studies, uracil was identified as the active principle from Trionyx carapax. The protective effects of other nucleic acid components, and of xanthine are further investigated.
Alanine Transaminase↗
Effect of pretreatment of rats with uracil on liver injuries induced by D-galactosamine and allyl alcohol.
Uracil was previously shown by us to be the active principle of Trionyx carapax. In this study, we show that pretreatment with uracil protects rats against hepatic injury induced by allyl alcohol and by D-galactosamine.
1-Propanol↗
[Localization of extracellular matrix in human trabecular tissues].
Trabecular tissues taken from seven normal human eyes were subjected to this study. Localization of various types of collagen I, III, IV, V, VI, proteoglycan, laminin, fibronectin, elastin and thrombospondin in the human trabecular meshwork was investigated using immunohistochemical methods. The study revealed the presence and localization of the collagen types I, III, IV, V, VI, proteoglycan, laminin, fibronectin, elastin, and thrombospondin in the trabecular meshwork.
Aged↗
Protective effect of Trionyx carapax on CCl4-induced hepatic injury is mediated by uracil.
Oral administration of crude extracts of Trionyx carapax into rats was found to protect the liver from its CCl4-induced injury as judged by morphological and biochemical observations. The active principle was purified from crude extracts of Trionyx carapax by Sephadex G-75, Sephadex G-25, DEAE-cellulose and silica gel column chromatographies. The results of elemental analysis, infrared and mass spectroscopy demonstrated the purified component to be identical to uracil. Upon administration, authentic uracil exhibited the protective effects on CCl4-induced hepatic injury, a pattern identical to or very similar to that observed with crude extracts of Trionyx carapax. Thus it is concluded that uracil is the active component responsible for protection from CCl4-induced hepatic injury.
Administration, Oral↗
Acceleration of bovine neurofilament L assembly by deprivation of acidic tail domain.
Functions of the tail region of neurofilament L have, to date, not been clearly elucidated. Bovine neurofilament L was cleaved into tail-less neurofilament L (50 kDa) and a tail fragment (19 kDa), by thrombin. Tail-less neurofilament L was deficit of the highly acidic domain of the tail region (approximately 77% of the entire region). Assembly of tail-less neurofilament L. was observed to be accelerated by both fluorometric and centrifugal measurements, compared with intact neurofilament L. The critical concentration of tail-less neurofilament L, which constitutes the constant unassembled pool, was approximately 0.25-times lower than that of neurofilament L. Under physiological conditions, tail-less neurofilament L formed a ribbon-like structure, whereas tail-less neurofilament L could form 10-nm filaments in an extremely low ionic-strength buffer in the presence of 1 mM MgCl2. An affinity-purified antibody directed against the tail fragment also accelerated neurofilament L assembly. The tail fragment neither coassembled with neurofilament L nor affect neurofilament L assembly. The acidic domain of the tail region may regulate neurofilament assembly and may be involved in 10-nm filament formation under physiological conditions.
Amino Acid Sequence↗
Domain structure of a human general transcription initiation factor, TFIIF.
The structural and functional domains of a general transcription initiation factor, TFIIF (RAP30/74, FC), have been investigated using various deletion mutants of each subunit, both in vivo and in vitro. An in vivo assay showed that the N-terminal sequence containing residues of 1-110 of RAP30 that is located close to a sigma homology region interacts with a minimum sequence of residues 62-171 of RAP74 to form a heteromeric interaction. Reconstitution of in vitro transcription activity by deletion mutants of RAP74 clearly indicated that both N-terminal residues 73-205 and C-terminal residues 356-517 are essential for full activity, the former interacting with RAP30, thus complexing with RNA polymerase II. From these data, the functional significance of domain structure of TFIIF is discussed in terms of its sigma homology sequences and complex formation with RNA polymerase II in the initiation and elongation of transcription.
Amino Acid Sequence↗
Assignment of the human GTF2F1 gene to chromosome 19p13.3.
TFIIF (also termed FC) is a general transcription initiation factor that binds to RNA polymerase II and recruits it to a promoter. TFIIF is a heterodimer composed of 74-kDa (RAP74; gene symbol GTF2F1) and 30-kDa (RAP30; gene symbol GTF2F2) subunits. Here we report the mapping of the human GTF2F1 gene to band 19p13.3. Localization was performed by fluorescence in situ hybridization using the human RAP74 genomic cosmid clone as the probe.
Chromosome Banding↗