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S Morino

Publications and source records attributed to S Morino.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effect of mRNA cap structure on eIF-4E phosphorylation and cap binding analyses using Ser209-mutated eIF-4Es.

The in vitro phosphorylation of human recombinant eIF-4E by protein kinase C was most effective in the absence of m7GTP, supporting a 'performed complex model' as the mRNA binding step of initiation, i. e., eIF-4E first forms an initiation complex eIF-4F and is phosphorylated before interacting with mRNA. On the other hand, the comparison of m7GTP-binding ability of wild-type eIF-4E with those of four Ser209-mutated ones (S209A, S209D, S209E and S209K) showed that the addition of anionic charge on Ser209 increases the cap affinity of eIF-4E by repressing the release of the cap from the complex, not by increasing the complex formation, suggesting the importance of a retractable ionic bridge between Ser209 and Lys159 in controlling the cap binding by eIF-4E phosphorylation.

Binding Sites↗
PubMed1998

Expression of a synthetic gene for initiation factor 4E-binding protein 1 in Escherichia coli and its interaction with eIF-4E and eIF-4E x m7GTP complex.

An artificial gene coding for the human initiation factor (eIF) 4E-binding protein 1 (4E-BP1) was chemically synthesized and cloned. Although the expression of the 4E-BP1 gene alone has not yet been accomplished, the gene was expressed in Escherichia coli [BL21(DE3)] as a fusion gene with the glutathione-S-transferase (GST) gene using a prokaryotic gene fusion vector (pGEX-4T-2), which contains a gene sequence coding the cleavage site for a specific protease, alpha-thrombin. The fusion gene product was purified to homogeneity by glutathione Sepharose-4B affinity column chromatography. It was shown by m7GTP- and glutathione-affinity chromatography that the binding ability of 4E-BP1 to eIF-4E is nearly the same as that to the eIF-4E x m7GTP complex, implying different binding sites of eIF-4E and its nonallosteric obligation for 4E-BP1 and mRNA cap structure. In contrast with the binding of eIF-4E to the mRNA cap structure, where some functional amino acids play an important role in the binding, the binding to 4E-BP1 was suggested to occur via multiple nonspecific interactions.

Amino Acid Sequence↗
PubMed1998

A novel functional human eukaryotic translation initiation factor 4G.

Mammalian eukaryotic translation initiation factor 4F (eIF4F) is a cap-binding protein complex consisting of three subunits: eIF4E, eIF4A, and eIF4G. In yeast and plants, two related eIF4G species are encoded by two different genes. To date, however, only one functional eIF4G polypeptide, referred to here as eIF4GI, has been identified in mammals. Here we describe the discovery and functional characterization of a closely related homolog, referred to as eIF4GII. eIF4GI and eIF4GII share 46% identity at the amino acid level and possess an overall similarity of 56%. The homology is particularly high in certain regions of the central and carboxy portions, while the amino-terminal regions are more divergent. Far-Western analysis and coimmunoprecipitation experiments were used to demonstrate that eIF4GII directly interacts with eIF4E, eIF4A, and eIF3. eIF4GII, like eIF4GI, is also cleaved upon picornavirus infection. eIF4GII restores cap-dependent translation in a reticulocyte lysate which had been pretreated with rhinovirus 2A to cleave endogenous eIF4G. Finally, eIF4GII exists as a complex with eIF4E in HeLa cells, because eIF4GII and eIF4E can be purified together by cap affinity chromatography. Taken together, our findings indicate that eIF4GII is a functional homolog of eIF4GI. These results may have important implications for the understanding of the mechanism of shutoff of host protein synthesis following picornavirus infection.

Amino Acid Sequence↗
PubMed1998

Early neurologic complications following allogeneic bone marrow transplant for leukemia: a prospective study.

BACKGROUND: Bone marrow transplant (BMT) is used for both neoplastic and nonneoplastic diseases. Following BMT, particularly during the first 3 months, patients have a number of neurologic complications. We evaluated the early neurologic complications following BMT and their influence on survival. METHODS: We prospectively followed 115 consecutive patients having BMT for leukemia, for a median period of 90 days after transplantation. RESULTS: Sixty-four patients (56%) had neurologic complications. Sixteen developed more than one complication. Twenty-seven patients (25%) had major neurologic complications: metabolic encephalopathy (8), seizures (8), psychiatric symptoms (3), cerebral hemorrhage (1), cerebral abscess (1), leukemic meningitis (1), peripheral neuropathies (5), and myopathies (2). Forty patients (35%) had minor complications, including headache (16) and tremor (31). Major neurologic complications occurred after engraftment in most patients. Metabolic encephalopathy correlated with graft-versus-host disease (GVHD) (p < 0.03). Seven percent of patients had generalized seizures that occurred without signs of structural cerebral lesions. Probability of survival at day 90 was lower in patients with than in those without major central nervous system complications (63% versus 87.5%, p < 0.01). CONCLUSIONS: Neurologic complications are frequent during the first 3 months following BMT and affect patient survival. Drug neurotoxicity and acute GVHD are the main factors influencing their occurrence.

Adolescent↗
PubMed1997

Selegiline in the treatment of hypersomnolence in myotonic dystrophy: a pilot study.

Patients with myotonic dystrophy frequently complain of hypersomnolence, a symptom which seriously restricts their social life. The pathogenesis of this symptom is a matter of debate: it has been attributed to both alveolar hypoventilation and pathological changes in the brainstem. As selegiline has been shown to reduce the number of sleep attacks in nacrolepsy, we tested whether hypersomnolence in myotonic dystrophy would respond to the same treatment. Ten patients with myotonic dystrophy received selegiline/placebo (20 mg daily) in a double-blind crossover trial. We monitored daytime sleepiness by means of a multiple sleep latency test. Treatment appeared to be well tolerated but did not alter hypersomnolence in myotonic dystrophy. Further studies to assess the effect of higher doses of selegiline are warranted.

Adult↗
PubMed1997

Randomized placebo-controlled trial of mitoxantrone in relapsing-remitting multiple sclerosis: 24-month clinical and MRI outcome.

We designed a randomized, placebo-controlled, multicentre trial involving 51 relapsing-remitting multiple sclerosis patients to determine the clinical efficacy of mitoxantrone treatment over 2 years. Patients were allocated either to the mitoxantrone group (27 patients receiving I.V. infusion of mitoxantrone every month for 1 year at the dosage of 8 mg/m2) or to the placebo group (24 patients, receiving I.V. infusion of saline every month for 1 year) using a centralized randomization system. Disability at entry and at 12-24 months was evaluated by four blinded neurologists trained in the application of the Kurtzke Expanded Disability Scale (EDSS). In addition, the number and clinical characteristics of the exacerbations over the 24 months were recorded by the local investigators. MRI, at 0, 12 and 24 months, was performed with a 0.2 T permanent unit. MRI data were analysed by two blinded neuroradiologists. All patients underwent a clinical evaluation. A statistically significant difference in the mean number of exacerbations was observed between the mitoxantrone group and placebo group both during the 1st and the 2nd year. Although there was no statistically significant benefit in terms of mean EDSS progression over 2 years, the proportion of patients with confirmed progression of the disease, as measured by a one point increase on the EDSS scale, was significantly reduced at the 2nd year evaluation in the mitoxantrone group. Forty-two (23 mitoxantrone, 19 placebo) patients underwent all MRI examinations during the 24-month period. We observed a trend towards a reduction in the number of new lesions on T2-weighted images in the mitoxantrone group. Our study suggests that mitoxantrone might be effective in reducing disease activity, both by decreasing the mean number of exacerbations and by slowing the clinical progression sustained by most patients after 1 year from the end of treatment.

Adjuvants, Immunologic↗
PubMed1996

Mutation of the cysteine residues in human initiation factor 4E: effects on mRNA cap binding ability.

To investigate the role of four Cys residues of eukaryotic initiation factor (eIF)-4E in the recognition of the mRNA cap structure, single, double and quadruple mutant genes which encoded the Ala residues in the place of the respective Cys residues were prepared using a synthetic human eIF-4E gene by the site-directed mutagenesis, and were expressed in E. coli with the same way as the wild type. The cap binding abilities of respective mutated eIF-4Es were compared with that of the wild-type by m7GTP affinity chromatography. The results suggest that, although all four of Cys residues participate in the recognition of the mRNA cap structure, they contribute indirectly to the stabilization of overall tertiary structure, especially of the cap binding pocket, rather than by direct interaction. A comparison among the cap binding abilities of single, double and quadruple mutants indicated no existence of internal disulfide bonds in eIF-4E.

Escherichia coli↗
PubMed1996

Analysis of the mRNA cap-binding ability of human eukaryotic initiation factor-4E by use of recombinant wild-type and mutant forms.

In order to identify the amino acid residues necessary for the selective recognition of the mRNA cap structure by human eukaryotic initiation factor-4E (eIF-4E), which plays a central role in the first step of mRNA translation, we prepared recombinant wild-type and fourteen mutant forms and compared their cap-binding abilities by affinity chromatography. By the direct expression of a synthetic gene encoding human eIF-4E as the soluble form in Escherichia coli and the application on a 7-methylguanosine-5'-triphosphate-Sepharose 4B cap affinity column, pure recombinant eIF-4E was prepared; the optimum pH for the binding of the mRNA cap was 7.5. Among the amino acid residues conserved among various eIF-4E species, each of 14 functional residues was replaced with a nonpolar amino acid (alanine or leucine). All mutant eIF-4E genes, which were constructed by site-directed mutagenesis, were expressed in the same way as the wild type, and their cap-binding abilities were compared with that of the wild type. Consequently, all eight tryptophan residues. Glu103, and two histidine residues at positions 37 and 200 in human recombinant eIF-4E were suggested to be important for the recognition of the mRNA cap structure through direct interaction and/or indirect contributions. Indirect contributions included the construction of the overall protein structure, especially the cap-binding pocket.

Amino Acid Sequence↗
PubMed1996

Chorea in primary antiphospholipid syndrome.

A 12-year-old girl with chorea, thrombocytopenia and false positive VDRL had negative serological tests for SLE, but high titre of antiocardiolipine antibodies. Primary antiphospholipid antibody syndrome is rarely complicated by chorea, but should be taken into consideration in patients who do not fulfill the diagnostic criteria for SLE.

Anti-Inflammatory Agents↗
PubMed1996

Reversal of encephalopathy during treatment with amphotericin-B.

A case of reversible encephalopathy during treatment with Amphotericin-B (AMB) is described. The comparison of the clinical course of AMB encephalopathy with total dose of AMB, cranial radiotherapy and MRI data available in previously reported cases, shows that this complication is characterized by a progressive, dose-dependent course, possibly influenced by cranial irradiation.

Amphotericin B↗
PubMed1996

Crystallization and preliminary X-ray diffraction study of recombinant human eukaryotic initiation factor-4E.

Recombinant human eukaryotic initiation factor-4E (eIF-4E), purified by m7GTP-Sepharose 4B affinity chromatography, was used for crystallization. After concentration of the eIF-4E protein (7 mg/ml), the solution was subjected to crystallization by the hanging-drop method. Transparent needle crystals complexed with m7GTP were obtained from 50 mM 2-(N-morpholino)ethanesulfonic acid-KOH buffer (pH 6.5) containing 25% (w/v) polyethylene glycol 6000 and 0.2 M (NH4)2SO4. The crystals belong to tetragonal space group P4(1) or P4(3), of Z = 4, with unit-cell dimensions of a = 89.26, b = 89.26, and c = 38.51 angstrum, and diffract beyond 2.1 angstrum resolution. The Vm value was calculated to be 3.07 angstrum 3/Da, which indicates a solvent content of 59.9%.

Crystallization↗
PubMed1996

Myasthenia gravis in the elderly: a hospital based study.

To evaluate clinical characteristics and outcome of myasthenia gravis (MG) in aged patients (> 60yrs), we retrospectively reviewed a continuous series of 122 myasthenic patients observed from January 1968 through December 1994. Patients with congenital, neonatal, or penicillamine-induced myasthenia were excluded. Twenty-five subjects (20%) were > 60yrs. The male/female ratio was 3:2; 20% of patients had an ocular form and 86% were seropositive. Mediastinum CT scan revealed thymic changes in 14%. During the first five years of disease, 60% of patients with ocular form progressed towards a generalized form and 15% had clinical relapses. At the time of their last visit, 40% of patients were asymptomatic and 60% had improved on medication. No patient died because of myasthenia-related causes. This study shows that MG in aged patients is characterized by prevalence in males, low frequency of ocular forms, low frequency of positive mediastinum CT which suggests low frequency of thymomas, high frequency of progression of ocular forms, and good response to corticosteroid therapy.

Adrenal Cortex Hormones↗
PubMed1995

Signal-averaged electrocardiography in myotonic dystrophy.

We performed signal-averaged electrocardiography and 24-h ambulatory electrocardiographic monitoring in 53 patients with myotonic dystrophy to determine the incidence and clinical significance of ventricular late potentials. Patients were followed up for a mean period of 31 +/- 17 months (range 11-68 months). At entry, none of the patients had bundle branch block on 12-lead electrocardiogram and none had wall motion abnormalities on routine echocardiogram. Also, no patient had history of syncope or clinical evidence of ischemic heart disease or a documented sustained ventricular tachycardia. A group of 47 healthy subjects matched for age and sex also underwent signal-averaged electrocardiography for comparison with the patient group. Late potentials were diagnosed in the presence of at least two of the following measures: duration of the filtered QRS > 114 ms, root-mean-square voltage of the terminal 40 ms of the filtered QRS < 20 microV, and duration of the low-amplitude (< 40 microV) signals of terminal filtered QRS > 38 ms. Late potentials were more frequent in patients than in controls: 18 of the 53 patients (34%) showed late potentials compared with four of the 47 controls (8.5%) (P < 0.01). In 45 patients (85%) no ventricular ectopy (40 cases) or infrequent premature ventricular complexes (five cases) were detected on Holter monitoring. Complex ventricular arrhythmias were traced in the remaining eight patients. These were six of the 18 patients with, and two of the 45 patients without late potentials (33% vs. 6%, respectively; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1995

Noninvasive assessment of mitoxantrone cardiotoxicity in relapsing remitting multiple sclerosis.

Multiple sclerosis is the most common cause of neurologic disability in young adults. Recent reports have suggested that Mitoxantrone might be a candidate for clinical trials in multiple sclerosis patients. The authors studied 20 patients with relapsing remitting multiple sclerosis to evaluate cardiac toxicity during a one-year follow-up period. Patients were divided into 2 groups: group A, mitoxantrone treated patients (cumulative dose of 96 mg/m2); group B, placebo patients. The clinical course of multiple sclerosis was assessed using the Expanded Disability Status Scale and the number of relapses during the follow-up. Each patient had an electrocardiogram and a spectral and color flow Doppler echocardiographic examination at enrollment, and 6 and 12 months later, to investigate cardiac toxicity. The mean exacerbation rate was reduced significantly in group A patients. No significant differences in the electrocardiograms or the echocardiographic parameters of systolic and diastolic function were noted between the two groups or in group A during the follow-up. Mitoxantrone treatment seems able to improve the clinical course of relapsing remitting multiple sclerosis patients. It does not show any cardiac toxicity in selected patients at this dosage.

Adolescent↗
PubMed1995

A controlled study of potential risk factors preceding exacerbation in multiple sclerosis.

A wide variety of potential risk factors for acute exacerbations in multiple sclerosis were evaluated in a one year case-control study. Eighty nine consecutive patients with clinically definite multiple sclerosis and relapsing remitting course presenting with a relapse between January and December 1992 were compared with patients matched for age, sex, and degree of disability, who did not experience clinical exacerbations during the same period. Only potential risk factors occurring in the three months preceding the interview were considered patients. Relapsing patients reported no significant increase in the frequency of any risk factor in the three month period before exacerbation compared with the control group. These results suggest that most relapses are not preceded by the conditions commonly considered as risk factors.

Adolescent↗
PubMed1995

Soluble expression of a synthetic gene for human translation initiation factor 4E in Escherichia coli.

In order to obtain the active form of recombinant human initiation factor (eIF) 4E effectively, an artificial synthetic gene was cloned into an expression vector (pMAL-p2) and the soluble expression was attempted in Escherichia coli under the control of a tac promoter. Two expression systems were finally constructed as a fusion protein with maltose-binding protein, which contain a recognition sequence for the site specific protease alpha-thrombin and factor Xa, respectively. Most of the fusion protein was induced as a soluble form. The soluble human eIF-4E digested from the fusion protein showed binding specificity for the m7GTP affinity column.

Amino Acid Sequence↗